diff --git a/docs/operations.md b/docs/operations.md
index 5a9b8fd..813e753 100644
--- a/docs/operations.md
+++ b/docs/operations.md
@@ -42,6 +42,42 @@ left on the employee's wallet. It was never settled and expires on its own;
 that is the deliberate price of not pricing the period a second time just
 to run a balance check.
 
+## Pricing a back-dated period
+
+A period whose payday is **today or ahead** is priced by LNbits itself —
+`create_invoice(amount, currency)` does the conversion, and nothing here
+touches the network. Every pricing mode agrees in that case.
+
+A period whose payday is **in the past** is where the modes diverge:
+
+| mode | converts at | use when |
+|---|---|---|
+| `payday` (default) | BTC's value on the payday | the expense belongs to that date |
+| `current` | today's rate | the debt reads "we owe EUR 800, whenever it settles" |
+| `manual` | a rate you state (`100000` EUR/BTC) | the figure was agreed, not looked up |
+
+Set per contract; overridable per payout via `pricing_mode` / `manual_rate`
+on `pay-now`, which is how you enter one back-dated payment without editing
+the contract.
+
+Historical rates come from `rates.py` — Kraken's daily OHLC series first
+(one request covers every date in a backfill), CoinGecko by date as the
+fallback for currencies Kraken does not quote. **Not** from LNbits' own
+exchange providers: those are spot tickers with no date parameter, and the
+rate history behind the admin chart is RAM-only, single-currency and wiped
+on restart.
+
+Where payroll converts, it hands `create_invoice` a **sat** amount, because
+`create_invoice` always prices fiat itself and cannot be told a rate. The
+rate used and its source are recorded on the payout row either way — in
+`current` mode read back off the invoice LNbits priced, not recomputed.
+
+**A rate that cannot be established fails the period.** There is deliberately
+no fallback to today's rate: one that moved 30% since the payday would pay
+30% off and record nothing about it. The failure goes through the same
+retry-then-pause path as an underfunded wallet, and names the date and
+currency it could not price.
+
 ## What a failure does
 
 A failed period does **not** advance `periods_done`, so the next tick
diff --git a/migrations.py b/migrations.py
index 282e1fc..b82e7d1 100644
--- a/migrations.py
+++ b/migrations.py
@@ -88,3 +88,27 @@ async def m002_payouts(db):
         "CREATE INDEX payroll.idx_payouts_employee_wallet "
         "ON payouts (employee_wallet);"
     )
+
+
+async def m003_pricing_mode(db):
+    """Let a back-dated period be priced at the day it was due.
+
+    Until now every payout converted at whatever the rate was when it
+    settled, which silently misprices a period paid late. The contract now
+    carries how to convert, and each payout records the rate it actually
+    used plus where that rate came from — so a figure in the ledger can be
+    explained months later instead of merely trusted.
+
+    Defaults preserve existing behaviour for anything already in flight:
+    every live payday is today or ahead, and for those all three modes agree
+    on using LNbits' own live pricing.
+    """
+    await db.execute(
+        "ALTER TABLE payroll.contracts "
+        "ADD COLUMN pricing_mode TEXT NOT NULL DEFAULT 'payday';"
+    )
+    await db.execute("ALTER TABLE payroll.contracts ADD COLUMN manual_rate REAL;")
+    await db.execute("ALTER TABLE payroll.payouts ADD COLUMN rate REAL;")
+    await db.execute(
+        "ALTER TABLE payroll.payouts ADD COLUMN rate_source TEXT NOT NULL DEFAULT '';"
+    )
diff --git a/models.py b/models.py
index 15ccaac..524224f 100644
--- a/models.py
+++ b/models.py
@@ -55,6 +55,25 @@ class Frequency(str, Enum):
     yearly = "yearly"
 
 
+class PricingMode(str, Enum):
+    """How a period's fiat amount becomes a sat amount.
+
+    Only ever matters for a payday in the past — for a payday that is today
+    or ahead, all three agree and LNbits' own live pricing is used.
+    """
+
+    # Convert at what BTC was worth on the payday itself. The default: a
+    # back-dated period is priced as of when it was due, not when somebody
+    # got round to paying it.
+    payday = "payday"
+    # Convert at today's rate. Correct when the obligation is understood as
+    # "we owe them EUR 800, whenever it settles".
+    current = "current"
+    # Convert at a rate the operator states outright (e.g. 100000 EUR/BTC),
+    # for a figure that was agreed rather than looked up.
+    manual = "manual"
+
+
 class ContractStatus(str, Enum):
     active = "active"  # eligible for payout on every scheduler tick
     paused = "paused"  # keeps its schedule position, pays nothing
@@ -101,6 +120,19 @@ class CreateContract(BaseModel):
     # months of back-pay in one tick.
     backfill: bool = False
 
+    # How to price a back-dated period. Irrelevant for a sat-denominated
+    # contract, and irrelevant for any payday that is not in the past.
+    pricing_mode: PricingMode = PricingMode.payday
+    # Units of `currency` per whole BTC. Required by, and only read under,
+    # PricingMode.manual.
+    manual_rate: float | None = None
+
+    @validator("manual_rate")
+    def _positive_rate(cls, v: float | None) -> float | None:
+        if v is not None and v <= 0:
+            raise ValueError("manual_rate must be positive")
+        return v
+
     @validator("start_date")
     def _valid_date(cls, v: str) -> str:
         datetime.strptime(v, "%Y-%m-%d")  # raises for anything malformed
@@ -159,6 +191,8 @@ class UpdateContract(BaseModel):
     total_periods: int | None = None
     label: str | None = None
     memo: str | None = None
+    pricing_mode: PricingMode | None = None
+    manual_rate: float | None = None
 
     @validator("amount")
     def _positive_amount(cls, v: float | None) -> float | None:
@@ -239,6 +273,14 @@ class Payout(BaseModel):
     payment_hash: str | None = None
     detail: str = ""
 
+    # Units of `currency` per whole BTC actually used for this period, and
+    # which of the pricing modes produced it. For a live conversion the rate
+    # is read back off the invoice LNbits priced rather than recomputed, so
+    # the row records what happened and not an approximation of it. Null on
+    # a sat contract, and on a failure that never got as far as pricing.
+    rate: float | None = None
+    rate_source: str = ""  # "current" | "payday" | "manual" | "" (sat / none)
+
     created_at: datetime = Field(default_factory=_now)
 
     @property
diff --git a/rates.py b/rates.py
new file mode 100644
index 0000000..a0a9910
--- /dev/null
+++ b/rates.py
@@ -0,0 +1,140 @@
+"""Historical BTC rates, for pricing a payout at the day it was due.
+
+LNbits cannot answer this. Its eight exchange providers are spot tickers
+with no date parameter, and the rate history behind the admin chart lives
+in `TransientSettings` — RAM only, wiped on restart, capped at
+`lnbits_exchange_history_size` points, and collected for a single currency
+(`lnbits_default_accounting_currency`). Useful for a monitoring graph;
+useless for "what was BTC worth on the 15th".
+
+So payroll asks a date-aware API directly.
+
+**Kraken first.** One `OHLC?interval=1440` request returns ~720 daily
+candles, so a twelve-period backfill costs a single call and every date is
+served from the parsed series. It is also already one of the providers
+LNbits itself trusts.
+
+**CoinGecko second**, for currencies Kraken lists no pair for. It is
+addressed by date rather than by series, so it costs one request per date —
+fine as a fallback, bad as a default against free-tier rate limits.
+
+Both return None rather than raising. A rate that cannot be established is
+a payout that must not happen: the caller records a failed period and lets
+a human decide, which is the same thing an underfunded wallet does. The one
+outcome this module must never produce is a plausible-looking wrong number.
+"""
+
+from datetime import date, datetime, timedelta, timezone
+
+import httpx
+from loguru import logger
+
+# Kraken quotes bitcoin as XBT. Its response key is *not* predictable
+# ("XXBTZEUR", "XBTUSDT", …), so the series is read positionally instead of
+# by reconstructing the name.
+_KRAKEN_URL = "https://api.kraken.com/0/public/OHLC"
+_COINGECKO_URL = "https://api.coingecko.com/api/v3/coins/bitcoin/history"
+
+_TIMEOUT = 15.0
+
+# A daily series is only appended to once a day, so re-fetching more often
+# than this buys nothing. Keeps a backfill plus every retry to one request.
+_CACHE_TTL = timedelta(hours=6)
+
+# currency -> (fetched_at, {day: close})
+_series_cache: dict[str, tuple[datetime, dict[date, float]]] = {}
+
+
+def _now() -> datetime:
+    return datetime.now(timezone.utc)
+
+
+async def _kraken_series(currency: str) -> dict[date, float]:
+    """Daily closes for XBT/<currency>, keyed by UTC day. Empty if the pair
+    is unknown or the request fails."""
+    cached = _series_cache.get(currency)
+    if cached and _now() - cached[0] < _CACHE_TTL:
+        return cached[1]
+
+    params = {"pair": f"XBT{currency}", "interval": "1440"}
+    async with httpx.AsyncClient() as client:
+        response = await client.get(_KRAKEN_URL, params=params, timeout=_TIMEOUT)
+        response.raise_for_status()
+        payload = response.json()
+
+    if payload.get("error"):
+        # Unknown pair is the ordinary case here, not an incident — it just
+        # means this currency needs the fallback.
+        logger.debug(f"payroll: kraken has no XBT{currency} series: {payload['error']}")
+        return {}
+
+    result = payload.get("result", {})
+    keys = [k for k in result if k != "last"]
+    if not keys:
+        return {}
+
+    series = {
+        datetime.fromtimestamp(candle[0], tz=timezone.utc).date(): float(candle[4])
+        for candle in result[keys[0]]
+    }
+    _series_cache[currency] = (_now(), series)
+    return series
+
+
+async def _coingecko_rate(day: date, currency: str) -> float | None:
+    """Close for one specific day. One request per date — fallback only."""
+    params = {"date": day.strftime("%d-%m-%Y"), "localization": "false"}
+    async with httpx.AsyncClient() as client:
+        response = await client.get(_COINGECKO_URL, params=params, timeout=_TIMEOUT)
+        response.raise_for_status()
+        payload = response.json()
+
+    price = payload.get("market_data", {}).get("current_price", {})
+    value = price.get(currency.lower())
+    return float(value) if value else None
+
+
+async def historical_btc_rate(day: date, currency: str) -> float | None:
+    """Units of `currency` per whole BTC on `day`, or None if unknowable.
+
+    None is a legitimate answer — the date may predate the provider's
+    history, the currency may not be quoted anywhere, or the API may be
+    down. Callers must treat it as "do not pay", never as "use some other
+    number".
+    """
+    currency = currency.upper()
+    if currency == "SAT":
+        raise ValueError("sat-denominated contracts need no rate")
+
+    try:
+        series = await _kraken_series(currency)
+        if day in series:
+            return series[day]
+        if series:
+            logger.debug(
+                f"payroll: {day} outside kraken's XBT{currency} range "
+                f"({min(series)}..{max(series)}), trying coingecko"
+            )
+    except Exception as exc:  # network, malformed payload, anything
+        logger.warning(f"payroll: kraken rate lookup failed for {currency}: {exc}")
+
+    try:
+        rate = await _coingecko_rate(day, currency)
+        if rate:
+            return rate
+    except Exception as exc:
+        logger.warning(f"payroll: coingecko rate lookup failed for {currency}: {exc}")
+
+    logger.warning(f"payroll: no historical rate for {currency} on {day}")
+    return None
+
+
+def sats_for(amount: float, rate: float) -> int:
+    """`amount` of fiat in sats, at `rate` units-per-BTC.
+
+    Rounded to the nearest sat rather than truncated: over a year of
+    paydays, always rounding down would quietly shortchange the employee.
+    """
+    if rate <= 0:
+        raise ValueError("rate must be positive")
+    return round(amount / rate * 100_000_000)
diff --git a/services.py b/services.py
index f167e8c..f1123a0 100644
--- a/services.py
+++ b/services.py
@@ -33,7 +33,9 @@ from .models import (
     Frequency,
     Payout,
     PayoutStatus,
+    PricingMode,
 )
+from .rates import historical_btc_rate, sats_for
 
 # Frequencies that are an exact number of days: no calendar involved, so no
 # clamping is possible or needed.
@@ -187,6 +189,8 @@ class PeriodOutcome:
     detail: str = ""
     amount_msat: int | None = None
     payment_hash: str | None = None
+    rate: float | None = None
+    rate_source: str = ""
 
     @property
     def consumed(self) -> bool:
@@ -214,12 +218,86 @@ def _lock_for(contract_id: str) -> asyncio.Lock:
     return lock
 
 
+def _today() -> date:
+    return datetime.now(timezone.utc).date()
+
+
 def payout_memo(contract: Contract, payday: date) -> str:
     label = contract.memo or contract.label or "Payroll"
     return f"{label} — {payday.isoformat()}"
 
 
-async def pay_period(contract: Contract, index: int, payday: date) -> PeriodOutcome:
+class PricingError(ValueError):
+    """A period's sat amount could not be established.
+
+    Deliberately fatal for that period. The alternative — falling back to
+    today's rate when the payday's rate is unavailable — pays a materially
+    different amount than intended and hides it, which is exactly the class
+    of error nobody finds until an audit.
+    """
+
+
+@dataclass
+class Price:
+    """What to hand `create_invoice`, plus the provenance to record.
+
+    When `currency` is the contract's own, LNbits does the conversion and
+    `rate` is filled in afterwards from the invoice it priced — read back
+    rather than recomputed, so the ledger records what actually happened.
+    """
+
+    amount: float
+    currency: str
+    rate: float | None
+    source: str
+
+
+async def resolve_price(
+    contract: Contract,
+    payday: date,
+    today: date,
+    mode: PricingMode | None = None,
+    manual_rate: float | None = None,
+) -> Price:
+    """Decide what a period is worth, and say where the number came from.
+
+    `mode`/`manual_rate` override the contract's own settings for a single
+    call, which is how an operator prices one off-cycle payout differently
+    without editing the contract.
+    """
+    if contract.currency.lower() == "sat":
+        return Price(contract.amount, "sat", None, "")
+
+    mode = mode or contract.pricing_mode
+    manual_rate = manual_rate or contract.manual_rate
+
+    # A payday that is today or ahead needs no history: every mode agrees,
+    # and LNbits' own live pricing is the freshest source available.
+    if payday >= today or mode == PricingMode.current:
+        return Price(contract.amount, contract.currency, None, "current")
+
+    if mode == PricingMode.manual:
+        if not manual_rate:
+            raise PricingError("manual pricing selected but no rate given")
+        return Price(
+            sats_for(contract.amount, manual_rate), "sat", manual_rate, "manual"
+        )
+
+    rate = await historical_btc_rate(payday, contract.currency)
+    if rate is None:
+        raise PricingError(
+            f"no historical {contract.currency} rate available for {payday}"
+        )
+    return Price(sats_for(contract.amount, rate), "sat", rate, "payday")
+
+
+async def pay_period(
+    contract: Contract,
+    index: int,
+    payday: date,
+    mode: PricingMode | None = None,
+    manual_rate: float | None = None,
+) -> PeriodOutcome:
     """Move one period's money from the source wallet to the employee wallet.
 
     An internal invoice on the destination wallet, paid from the source
@@ -240,11 +318,23 @@ async def pay_period(contract: Contract, index: int, payday: date) -> PeriodOutc
         "payday": payday.isoformat(),
     }
 
+    try:
+        price = await resolve_price(contract, payday, _today(), mode, manual_rate)
+    except (PricingError, ValueError) as exc:
+        return PeriodOutcome(
+            index=index,
+            payday=payday,
+            status=PayoutStatus.failed,
+            detail=str(exc),
+        )
+    if price.source:
+        extra["rate_source"] = price.source
+
     try:
         invoice = await create_invoice(
             wallet_id=contract.employee_wallet,
-            amount=contract.amount,
-            currency=contract.currency,
+            amount=price.amount,
+            currency=price.currency,
             memo=memo,
             internal=True,
             extra=extra,
@@ -262,6 +352,13 @@ async def pay_period(contract: Contract, index: int, payday: date) -> PeriodOutc
     # invoice.amount is msat and is now the canonical figure for this period.
     amount_msat = invoice.amount
 
+    # For a live conversion LNbits stashes the rate it used on the payment;
+    # read it back rather than recomputing, so the ledger records the number
+    # that was actually applied.
+    rate = price.rate
+    if rate is None and price.source == "current":
+        rate = (invoice.extra or {}).get("btc_rate")
+
     source = await get_wallet(contract.source_wallet)
     if not source:
         return PeriodOutcome(
@@ -270,6 +367,8 @@ async def pay_period(contract: Contract, index: int, payday: date) -> PeriodOutc
             status=PayoutStatus.failed,
             detail="source wallet not found",
             amount_msat=amount_msat,
+            rate=rate,
+            rate_source=price.source,
         )
     if source.balance_msat < amount_msat:
         return PeriodOutcome(
@@ -282,6 +381,8 @@ async def pay_period(contract: Contract, index: int, payday: date) -> PeriodOutc
                 f"{amount_msat // 1000} sat required"
             ),
             amount_msat=amount_msat,
+            rate=rate,
+            rate_source=price.source,
         )
 
     try:
@@ -300,6 +401,8 @@ async def pay_period(contract: Contract, index: int, payday: date) -> PeriodOutc
             detail=f"payment failed: {exc}",
             amount_msat=amount_msat,
             payment_hash=invoice.payment_hash,
+            rate=rate,
+            rate_source=price.source,
         )
 
     return PeriodOutcome(
@@ -308,6 +411,8 @@ async def pay_period(contract: Contract, index: int, payday: date) -> PeriodOutc
         status=PayoutStatus.paid,
         amount_msat=amount_msat,
         payment_hash=invoice.payment_hash,
+        rate=rate,
+        rate_source=price.source,
     )
 
 
@@ -324,7 +429,7 @@ async def run_due_periods(
     retried on the next tick, because a failed period does not advance the
     contract's position.
     """
-    today = today or datetime.now(timezone.utc).date()
+    today = today or _today()
 
     async with _lock_for(contract.id):
         # Re-read under the lock: a manual run may have moved the position
@@ -386,6 +491,8 @@ async def _record(contract: Contract, outcome: PeriodOutcome) -> Payout:
             source_wallet=contract.source_wallet,
             payment_hash=outcome.payment_hash,
             detail=outcome.detail,
+            rate=outcome.rate,
+            rate_source=outcome.rate_source,
         )
     )
 
@@ -522,7 +629,7 @@ def resume(
 
     contract.status = ContractStatus.active
     if not catch_up:
-        today = today or datetime.now(timezone.utc).date()
+        today = today or _today()
         skipped_to = fast_forward_index(contract, today)
         if skipped_to != contract.periods_done:
             logger.info(
@@ -551,7 +658,11 @@ def cancel(contract: Contract) -> Contract:
 # ---------------------------------------------------------------------------
 
 
-async def pay_now(contract: Contract) -> Payout:
+async def pay_now(
+    contract: Contract,
+    mode: PricingMode | None = None,
+    manual_rate: float | None = None,
+) -> Payout:
     """Settle the contract's next period immediately, whatever the calendar
     says.
 
@@ -565,6 +676,10 @@ async def pay_now(contract: Contract) -> Payout:
     because `_settle`'s back-dated skip exists to stop a *new* contract
     firing surprise back-pay. An operator explicitly asking to pay a period
     is not a surprise.
+
+    `mode`/`manual_rate` price this one payout differently without editing
+    the contract — the case an operator hits when entering a payment that
+    happened weeks ago at a rate they already know.
     """
     async with _lock_for(contract.id):
         fresh = await crud.get_contract(contract.id)
@@ -582,9 +697,9 @@ async def pay_now(contract: Contract) -> Payout:
 
         index = contract.periods_done
         payday = occurrence_on(parse_start_date(contract), contract.frequency, index)
-        today = datetime.now(timezone.utc).date()
+        today = _today()
 
-        outcome = await pay_period(contract, index, payday)
+        outcome = await pay_period(contract, index, payday, mode, manual_rate)
         if payday > today and outcome.status == PayoutStatus.paid:
             outcome.detail = f"paid early on {today.isoformat()} (due {payday})"
 
diff --git a/static/js/index.js b/static/js/index.js
index abf6f95..4f88d7a 100644
--- a/static/js/index.js
+++ b/static/js/index.js
@@ -15,6 +15,12 @@ const FREQUENCIES = [
   {value: 'yearly', label: 'Yearly'}
 ]
 
+const PRICING_MODES = [
+  {value: 'payday', label: "Rate on the payday"},
+  {value: 'current', label: "Rate at settlement"},
+  {value: 'manual', label: 'Rate I enter'}
+]
+
 const STATUS_COLOUR = {
   active: 'positive',
   paused: 'warning',
@@ -45,7 +51,11 @@ function emptyContract() {
     total_periods: 12,
     label: '',
     memo: '',
-    backfill: false
+    backfill: false,
+    // Only ever consulted for a payday in the past; for a payday today or
+    // ahead every mode collapses to LNbits' own live pricing.
+    pricing_mode: 'payday',
+    manual_rate: null
   }
 }
 
@@ -69,6 +79,14 @@ window.app = Vue.createApp({
       frequencyOptions: FREQUENCIES,
 
       contractDialog: {show: false, data: emptyContract(), saving: false},
+      payNowDialog: {
+        show: false,
+        contract: null,
+        pricing_mode: 'payday',
+        manual_rate: null,
+        loading: false
+      },
+      pricingModes: PRICING_MODES,
       // Live calendar of whatever is currently typed into the dialog. The
       // cheapest moment to notice a wrong start date or frequency is before
       // anything is saved.
@@ -121,6 +139,7 @@ window.app = Vue.createApp({
           align: 'left',
           field: 'contract_id'
         },
+        {name: 'rate', label: 'Rate used', align: 'right', field: 'rate'},
         {name: 'attempt', label: 'Try', align: 'center', field: 'attempt'},
         {name: 'detail', label: 'Detail', align: 'left', field: 'detail'}
       ]
@@ -331,7 +350,9 @@ window.app = Vue.createApp({
           total_periods: d.open_ended ? null : Number(d.total_periods),
           label: d.label,
           memo: d.memo,
-          backfill: d.backfill
+          backfill: d.backfill,
+          pricing_mode: d.pricing_mode,
+          manual_rate: d.pricing_mode === 'manual' ? Number(d.manual_rate) : null
         })
         this.contractDialog.show = false
         Quasar.Notify.create({type: 'positive', message: 'Payroll line created'})
@@ -354,7 +375,9 @@ window.app = Vue.createApp({
           open_ended: contract.total_periods === null,
           total_periods: contract.total_periods,
           label: contract.label,
-          memo: contract.memo
+          memo: contract.memo,
+          pricing_mode: contract.pricing_mode,
+          manual_rate: contract.manual_rate
         }
       }
     },
@@ -372,7 +395,9 @@ window.app = Vue.createApp({
             frequency: d.frequency,
             total_periods: d.open_ended ? null : Number(d.total_periods),
             label: d.label,
-            memo: d.memo
+            memo: d.memo,
+            pricing_mode: d.pricing_mode,
+            manual_rate: d.pricing_mode === 'manual' ? Number(d.manual_rate) : null
           }
         )
         this.editDialog.show = false
@@ -416,33 +441,49 @@ window.app = Vue.createApp({
     },
 
     payNow(contract) {
-      LNbits.utils
-        .confirmDialog(
-          `Pay the next period of "${contract.label || contract.id}" now? ` +
-            'It is consumed even if its payday has not arrived yet.'
+      // A dialog rather than a confirm: paying a back-dated period is
+      // exactly when the operator may want a different rate than the
+      // contract's own, and that choice has to be made before it settles.
+      this.payNowDialog = {
+        show: true,
+        contract,
+        pricing_mode: contract.pricing_mode || 'payday',
+        manual_rate: contract.manual_rate,
+        loading: false
+      }
+    },
+
+    async confirmPayNow() {
+      const d = this.payNowDialog
+      const params = new URLSearchParams({pricing_mode: d.pricing_mode})
+      if (d.pricing_mode === 'manual' && d.manual_rate) {
+        params.append('manual_rate', String(d.manual_rate))
+      }
+      d.loading = true
+      try {
+        const {data} = await LNbits.api.request(
+          'POST',
+          `${API}/contracts/${d.contract.id}/pay-now?${params.toString()}`
         )
-        .onOk(async () => {
-          try {
-            const {data} = await LNbits.api.request(
-              'POST',
-              `${API}/contracts/${contract.id}/pay-now`
-            )
-            // A refused payout still returns a ledger row — surfacing its
-            // reason is the whole point of triggering one by hand.
-            Quasar.Notify.create({
-              type: data.status === 'paid' ? 'positive' : 'negative',
-              message:
-                data.status === 'paid'
-                  ? `Paid ${Math.round(data.amount_msat / 1000)} sat`
-                  : `Payout ${data.status}: ${data.detail}`,
-              timeout: data.status === 'paid' ? 3000 : 8000
-            })
-            this.getContracts()
-            this.getPayouts()
-          } catch (err) {
-            this._err(err, 'Could not pay now')
-          }
+        // A refused payout still returns a ledger row — surfacing its
+        // reason is the whole point of triggering one by hand.
+        Quasar.Notify.create({
+          type: data.status === 'paid' ? 'positive' : 'negative',
+          message:
+            data.status === 'paid'
+              ? `Paid ${Math.round(data.amount_msat / 1000)} sat` +
+                (data.rate ? ` at ${data.rate.toLocaleString()} / BTC` : '')
+              : `Payout ${data.status}: ${data.detail}`,
+          timeout: data.status === 'paid' ? 4000 : 9000
         })
+        d.show = false
+        this.getContracts()
+        this.getPayouts()
+      } catch (err) {
+        this._err(err, 'Could not pay now')
+      } finally {
+        d.loading = false
+      }
     },
 
     deleteContract(contract) {
diff --git a/templates/payroll/index.html b/templates/payroll/index.html
index d28a7a2..0e5ca71 100644
--- a/templates/payroll/index.html
+++ b/templates/payroll/index.html
@@ -151,6 +151,18 @@
               </q-td>
             </template>
 
+            <template v-slot:body-cell-rate="props">
+              <q-td :props="props">
+                <span v-if="props.row.rate">
+                  ${ Math.round(props.row.rate).toLocaleString() }
+                  <span :style="{opacity: 0.6, fontSize: '0.8em'}">
+                    ${ props.row.rate_source }
+                  </span>
+                </span>
+                <span v-else :style="{opacity: 0.4}">—</span>
+              </q-td>
+            </template>
+
             <template v-slot:body-cell-detail="props">
               <q-td :props="props">
                 <span :style="{opacity: 0.75, fontSize: '0.85em'}">
@@ -252,6 +264,22 @@
       <q-input outlined dense v-model="contractDialog.data.memo"
         label="Payment memo" hint="What the employee sees on the payment"></q-input>
 
+      <div class="row q-col-gutter-sm">
+        <div class="col-7">
+          <q-select outlined dense v-model="contractDialog.data.pricing_mode"
+            :options="pricingModes" emit-value map-options
+            :disable="contractDialog.data.currency === 'sat'"
+            label="Price a late payday at"
+            hint="Only applies to a payday already in the past"></q-select>
+        </div>
+        <div class="col-5">
+          <q-input outlined dense type="number" step="any"
+            v-model.number="contractDialog.data.manual_rate"
+            :disable="contractDialog.data.pricing_mode !== 'manual'"
+            :label="'Rate (' + contractDialog.data.currency + '/BTC)'"></q-input>
+        </div>
+      </div>
+
       <q-toggle v-model="contractDialog.data.backfill"
         label="Pay paydays that already passed">
         <q-tooltip>
@@ -324,6 +352,19 @@
             label="Number of payments"></q-input>
         </div>
       </div>
+      <div class="row q-col-gutter-sm">
+        <div class="col-7">
+          <q-select outlined dense v-model="editDialog.data.pricing_mode"
+            :options="pricingModes" emit-value map-options
+            label="Price a late payday at"></q-select>
+        </div>
+        <div class="col-5">
+          <q-input outlined dense type="number" step="any"
+            v-model.number="editDialog.data.manual_rate"
+            :disable="editDialog.data.pricing_mode !== 'manual'"
+            label="Rate per BTC"></q-input>
+        </div>
+      </div>
       <q-input outlined dense v-model="editDialog.data.label" label="Label"></q-input>
       <q-input outlined dense v-model="editDialog.data.memo"
         label="Payment memo"></q-input>
@@ -335,6 +376,38 @@
   </q-card>
 </q-dialog>
 
+<!-- ==================================================== pay now -->
+<q-dialog v-model="payNowDialog.show">
+  <q-card style="width: 460px; max-width: 95vw">
+    <q-card-section>
+      <div class="text-h6">Pay the next period now</div>
+      <div v-if="payNowDialog.contract" class="text-caption"
+        :style="{opacity: 0.7}">
+        ${ payNowDialog.contract.label || payNowDialog.contract.employee_username }
+        — ${ payNowDialog.contract.amount } ${ payNowDialog.contract.currency }.
+        The period is consumed even if its payday has not arrived yet.
+      </div>
+    </q-card-section>
+    <q-card-section class="q-gutter-md">
+      <q-select outlined dense v-model="payNowDialog.pricing_mode"
+        :options="pricingModes" emit-value map-options
+        label="Price it at"
+        hint="Ignored unless the payday is already in the past"></q-select>
+      <q-input outlined dense type="number" step="any"
+        v-model.number="payNowDialog.manual_rate"
+        :disable="payNowDialog.pricing_mode !== 'manual'"
+        label="Rate per BTC"
+        hint="e.g. 100000 for 100,000 per BTC"></q-input>
+    </q-card-section>
+    <q-card-actions align="right">
+      <q-btn flat label="Cancel" v-close-popup></q-btn>
+      <q-btn color="primary" label="Pay now" :loading="payNowDialog.loading"
+        :disable="payNowDialog.pricing_mode === 'manual' && !payNowDialog.manual_rate"
+        @click="confirmPayNow"></q-btn>
+    </q-card-actions>
+  </q-card>
+</q-dialog>
+
 <!-- =================================================== schedule -->
 <q-dialog v-model="scheduleDialog.show">
   <q-card style="width: 420px; max-width: 95vw">
diff --git a/tests/conftest.py b/tests/conftest.py
index 3bd7a28..99fc158 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -7,7 +7,7 @@ keeping `services` split into a pure half and an effectful half.
 
 from datetime import datetime, timezone
 
-from ..models import Contract, ContractStatus, Frequency
+from ..models import Contract, ContractStatus, Frequency, PricingMode
 
 
 def make_contract(
@@ -22,6 +22,8 @@ def make_contract(
     currency: str = "sat",
     backfill: bool = False,
     created_at: str = "2026-01-01",
+    pricing_mode: PricingMode = PricingMode.payday,
+    manual_rate: float | None = None,
 ) -> Contract:
     return Contract(
         id=contract_id,
@@ -37,6 +39,8 @@ def make_contract(
         periods_done=periods_done,
         status=status,
         backfill=backfill,
+        pricing_mode=pricing_mode,
+        manual_rate=manual_rate,
         created_at=datetime.strptime(created_at, "%Y-%m-%d").replace(
             tzinfo=timezone.utc
         ),
diff --git a/tests/test_payout.py b/tests/test_payout.py
index defff71..0157481 100644
--- a/tests/test_payout.py
+++ b/tests/test_payout.py
@@ -57,7 +57,7 @@ def payroll_stub(monkeypatch):
     async def fake_count_period_failures(_contract_id, _period_index):
         return stub.prior_failures
 
-    async def fake_pay_period(contract, index, payday):
+    async def fake_pay_period(contract, index, payday, mode=None, manual_rate=None):
         stub.attempted.append(index)
         paid = stub.outcome_status == PayoutStatus.paid
         return PeriodOutcome(
diff --git a/tests/test_pricing.py b/tests/test_pricing.py
new file mode 100644
index 0000000..8c5c908
--- /dev/null
+++ b/tests/test_pricing.py
@@ -0,0 +1,131 @@
+"""Pricing a period.
+
+`resolve_price` is where a back-dated payout stops being worth today's
+money. These pin down which mode wins when, and that an unavailable rate
+refuses rather than substitutes.
+"""
+
+import asyncio
+from datetime import date
+
+import pytest
+
+from .. import services
+from ..models import PricingMode
+from ..services import PricingError, resolve_price
+from .conftest import make_contract
+
+TODAY = date(2026, 8, 31)
+PAST = date(2026, 5, 15)
+PAST_RATE = 69743.26
+
+
+@pytest.fixture
+def historical(monkeypatch):
+    """Stub the lookup and record what it was asked for."""
+    asked = []
+
+    async def fake_rate(day, currency):
+        asked.append((day, currency))
+        return PAST_RATE if currency == "EUR" else None
+
+    monkeypatch.setattr(services, "historical_btc_rate", fake_rate)
+    return asked
+
+
+def eur(**kw):
+    return make_contract(currency="EUR", amount=800, **kw)
+
+
+def price(contract, payday=PAST, today=TODAY, **kw):
+    return asyncio.run(resolve_price(contract, payday, today, **kw))
+
+
+# --- when history is irrelevant --------------------------------------------
+
+
+def test_a_payday_today_uses_live_pricing(historical):
+    """No mode needs history for a payday that has not passed — LNbits' own
+    conversion is the freshest source there is."""
+    p = price(eur(), payday=TODAY)
+    assert (p.currency, p.source) == ("EUR", "current")
+    assert p.amount == 800  # handed to create_invoice as fiat, unconverted
+    assert historical == []
+
+
+def test_a_future_payday_uses_live_pricing(historical):
+    p = price(eur(), payday=date(2026, 12, 1))
+    assert p.source == "current"
+    assert historical == []
+
+
+def test_a_sat_contract_never_prices_at_all(historical):
+    p = price(make_contract(currency="sat", amount=1000))
+    assert (p.amount, p.currency, p.rate, p.source) == (1000, "sat", None, "")
+    assert historical == []
+
+
+# --- the three modes -------------------------------------------------------
+
+
+def test_payday_mode_converts_at_the_paydays_rate(historical):
+    p = price(eur(pricing_mode=PricingMode.payday))
+    assert p.source == "payday"
+    assert p.currency == "sat"
+    assert p.rate == PAST_RATE
+    assert p.amount == round(800 / PAST_RATE * 1e8)
+    assert historical == [(PAST, "EUR")]
+
+
+def test_current_mode_ignores_the_past_payday(historical):
+    """The employee is owed EUR 800 and gets EUR 800 of bitcoin today."""
+    p = price(eur(pricing_mode=PricingMode.current))
+    assert (p.currency, p.source) == ("EUR", "current")
+    assert historical == []
+
+
+def test_manual_mode_uses_the_stated_rate(historical):
+    p = price(eur(pricing_mode=PricingMode.manual, manual_rate=100_000))
+    assert p.source == "manual"
+    assert p.rate == 100_000
+    assert p.amount == 800_000  # 800 EUR at 100k EUR/BTC == 0.008 BTC
+    assert historical == []
+
+
+def test_manual_mode_without_a_rate_refuses(historical):
+    with pytest.raises(PricingError):
+        price(eur(pricing_mode=PricingMode.manual))
+
+
+# --- per-call override -----------------------------------------------------
+
+
+def test_an_override_beats_the_contract(historical):
+    """Pricing one off-cycle payout differently must not require editing the
+    contract."""
+    contract = eur(pricing_mode=PricingMode.payday)
+    p = price(contract, mode=PricingMode.manual, manual_rate=50_000)
+    assert (p.source, p.rate) == ("manual", 50_000)
+    assert historical == []
+
+
+def test_an_override_rate_supplies_a_contract_that_has_none(historical):
+    p = price(eur(), mode=PricingMode.manual, manual_rate=50_000)
+    assert p.amount == round(800 / 50_000 * 1e8)
+
+
+# --- the refusal that matters ----------------------------------------------
+
+
+def test_an_unavailable_rate_refuses_rather_than_substituting(historical):
+    """The whole point: no silent fallback to today's rate. A rate that
+    moved 30% since the payday would otherwise pay 30% off, discovered only
+    on review."""
+    with pytest.raises(PricingError):
+        price(make_contract(currency="JPY", amount=800))
+
+
+def test_the_refusal_names_the_date_and_currency(historical):
+    with pytest.raises(PricingError) as exc:
+        price(make_contract(currency="JPY", amount=800))
+    assert "JPY" in str(exc.value) and "2026-05-15" in str(exc.value)
diff --git a/tests/test_rates.py b/tests/test_rates.py
new file mode 100644
index 0000000..e17eb9a
--- /dev/null
+++ b/tests/test_rates.py
@@ -0,0 +1,241 @@
+"""Historical rate lookup.
+
+The network is stubbed — what these pin down is the fallback order, the
+caching that keeps a backfill to one request, and above all that an
+unknowable rate comes back as None rather than as some other number.
+"""
+
+import asyncio
+from datetime import date, datetime, timedelta, timezone
+
+import pytest
+
+from .. import rates
+from ..rates import historical_btc_rate, sats_for
+
+
+@pytest.fixture(autouse=True)
+def _clear_cache():
+    rates._series_cache.clear()
+    yield
+    rates._series_cache.clear()
+
+
+class Recorder:
+    def __init__(self):
+        self.kraken_calls = 0
+        self.coingecko_calls = 0
+
+
+@pytest.fixture
+def stub(monkeypatch):
+    rec = Recorder()
+
+    async def fake_kraken(currency):
+        rec.kraken_calls += 1
+        if currency != "EUR":
+            return {}  # no such pair
+        return {date(2026, 5, 15): 69743.26, date(2026, 5, 16): 70120.0}
+
+    async def fake_coingecko(day, currency):
+        rec.coingecko_calls += 1
+        return 61000.0 if currency == "GBP" else None
+
+    monkeypatch.setattr(rates, "_kraken_series", fake_kraken)
+    monkeypatch.setattr(rates, "_coingecko_rate", fake_coingecko)
+    return rec
+
+
+# --- sourcing --------------------------------------------------------------
+
+
+def test_kraken_answers_without_touching_the_fallback(stub):
+    rate = asyncio.run(historical_btc_rate(date(2026, 5, 15), "EUR"))
+    assert rate == 69743.26
+    assert (stub.kraken_calls, stub.coingecko_calls) == (1, 0)
+
+
+def test_currency_kraken_does_not_quote_falls_through(stub):
+    rate = asyncio.run(historical_btc_rate(date(2026, 5, 15), "GBP"))
+    assert rate == 61000.0
+    assert stub.coingecko_calls == 1
+
+
+def test_date_outside_krakens_range_falls_through(stub):
+    """Kraken keeps ~2 years; an older payday has to go to CoinGecko."""
+    asyncio.run(historical_btc_rate(date(2019, 1, 1), "EUR"))
+    assert stub.coingecko_calls == 1
+
+
+def test_currency_is_case_insensitive(stub):
+    assert asyncio.run(historical_btc_rate(date(2026, 5, 15), "eur")) == 69743.26
+
+
+def test_sat_contracts_are_a_programming_error():
+    with pytest.raises(ValueError):
+        asyncio.run(historical_btc_rate(date(2026, 5, 15), "sat"))
+
+
+# --- the answer that must never be wrong -----------------------------------
+
+
+def test_unknowable_rate_returns_none_not_a_guess(stub):
+    """Neither source has it: the caller must get None so it can refuse to
+    pay, rather than a plausible number from the wrong day."""
+    assert asyncio.run(historical_btc_rate(date(2026, 5, 15), "JPY")) is None
+
+
+def test_a_failing_provider_does_not_propagate(monkeypatch, stub):
+    async def boom(_currency):
+        raise RuntimeError("kraken is down")
+
+    monkeypatch.setattr(rates, "_kraken_series", boom)
+    # GBP still resolves via the fallback despite the primary throwing.
+    assert asyncio.run(historical_btc_rate(date(2026, 5, 15), "GBP")) == 61000.0
+
+
+def test_both_providers_failing_returns_none(monkeypatch, stub):
+    async def boom(*_args):
+        raise RuntimeError("offline")
+
+    monkeypatch.setattr(rates, "_kraken_series", boom)
+    monkeypatch.setattr(rates, "_coingecko_rate", boom)
+    assert asyncio.run(historical_btc_rate(date(2026, 5, 15), "EUR")) is None
+
+
+# --- caching ---------------------------------------------------------------
+
+# These stub the HTTP layer rather than `_kraken_series`, so the real cache
+# path runs. Stubbing the function under test would make them pass even if
+# the cache were deleted.
+
+
+def _kraken_payload(days: int = 31) -> dict:
+    base = datetime(2026, 5, 1, tzinfo=timezone.utc)
+    candles = [
+        [int((base + timedelta(days=i)).timestamp()), "0", "0", "0", f"{70000 + i}"]
+        for i in range(days)
+    ]
+    return {"error": [], "result": {"XXBTZEUR": candles, "last": 0}}
+
+
+@pytest.fixture
+def http_stub(monkeypatch):
+    """Replace httpx.AsyncClient with one that counts requests."""
+    calls = {"n": 0}
+
+    class FakeResponse:
+        def __init__(self, payload):
+            self._payload = payload
+
+        def raise_for_status(self):
+            pass
+
+        def json(self):
+            return self._payload
+
+    class FakeClient:
+        async def __aenter__(self):
+            return self
+
+        async def __aexit__(self, *_exc):
+            return False
+
+        async def get(self, _url, params=None, timeout=None):
+            calls["n"] += 1
+            return FakeResponse(_kraken_payload())
+
+    monkeypatch.setattr(rates.httpx, "AsyncClient", FakeClient)
+    return calls
+
+
+def test_a_backfill_costs_one_request(http_stub):
+    """Twelve periods, one series fetch — the whole reason Kraken is primary
+    rather than the date-addressed API."""
+
+    async def run():
+        return [
+            await historical_btc_rate(date(2026, 5, 1) + timedelta(days=i), "EUR")
+            for i in range(12)
+        ]
+
+    got = asyncio.run(run())
+    assert got == [70000.0 + i for i in range(12)]
+    assert http_stub["n"] == 1
+
+
+def test_the_series_is_parsed_from_the_positional_key(http_stub):
+    """Kraken's result key is unpredictable ("XXBTZEUR", "XBTUSDT", ...), so
+    it is read positionally rather than reconstructed."""
+    assert asyncio.run(historical_btc_rate(date(2026, 5, 3), "EUR")) == 70002.0
+
+
+def test_a_stale_cache_entry_is_refetched(http_stub):
+    asyncio.run(historical_btc_rate(date(2026, 5, 1), "EUR"))
+    assert http_stub["n"] == 1
+
+    fetched_at, series = rates._series_cache["EUR"]
+    rates._series_cache["EUR"] = (
+        fetched_at - rates._CACHE_TTL - timedelta(minutes=1),
+        series,
+    )
+
+    asyncio.run(historical_btc_rate(date(2026, 5, 1), "EUR"))
+    assert http_stub["n"] == 2
+
+
+def test_a_kraken_error_payload_is_not_cached(monkeypatch):
+    """An unknown pair must not poison the cache — the next call should try
+    again rather than serve an empty series for six hours."""
+    calls = {"n": 0}
+
+    class FakeResponse:
+        def raise_for_status(self):
+            pass
+
+        def json(self):
+            return {"error": ["EQuery:Unknown asset pair"], "result": {}}
+
+    class FakeClient:
+        async def __aenter__(self):
+            return self
+
+        async def __aexit__(self, *_exc):
+            return False
+
+        async def get(self, _url, params=None, timeout=None):
+            calls["n"] += 1
+            return FakeResponse()
+
+    monkeypatch.setattr(rates.httpx, "AsyncClient", FakeClient)
+
+    async def no_fallback(_day, _currency):
+        return None
+
+    monkeypatch.setattr(rates, "_coingecko_rate", no_fallback)
+
+    asyncio.run(historical_btc_rate(date(2026, 5, 1), "XYZ"))
+    asyncio.run(historical_btc_rate(date(2026, 5, 1), "XYZ"))
+    assert calls["n"] == 2
+    assert "XYZ" not in rates._series_cache
+
+
+# --- conversion ------------------------------------------------------------
+
+
+def test_sats_for_converts_at_the_given_rate():
+    # 10 EUR at 69743.26 EUR/BTC
+    assert sats_for(10, 69743.26) == round(10 / 69743.26 * 1e8)
+
+
+def test_sats_for_rounds_rather_than_truncates():
+    """Truncating every payday would quietly shortchange the employee over
+    the life of a contract."""
+    assert sats_for(1, 3e8) == 0  # 0.333 sat -> 0
+    assert sats_for(2, 3e8) == 1  # 0.667 sat -> 1, not 0
+
+
+def test_sats_for_rejects_a_nonsense_rate():
+    for bad in (0, -1):
+        with pytest.raises(ValueError):
+            sats_for(10, bad)
diff --git a/views_api.py b/views_api.py
index 7218974..2d82d6d 100644
--- a/views_api.py
+++ b/views_api.py
@@ -30,6 +30,7 @@ from .models import (
     DirectoryUser,
     Payout,
     PayoutStatus,
+    PricingMode,
     SchedulePreview,
     SchedulePreviewRequest,
     UpdateContract,
@@ -95,6 +96,14 @@ async def _validate_terms(data: CreateContract) -> str:
             HTTPStatus.BAD_REQUEST, f"Unsupported currency '{data.currency}'."
         )
 
+    # Catch this now rather than as a failed payout weeks later, when the
+    # first back-dated period tries to price itself and finds no rate.
+    if data.pricing_mode == PricingMode.manual and not data.manual_rate:
+        raise HTTPException(
+            HTTPStatus.BAD_REQUEST,
+            "Manual pricing needs a rate (units of the currency per BTC).",
+        )
+
     return employee.display_name
 
 
@@ -301,7 +310,11 @@ async def api_contract_schedule(contract_id: str, count: int = 12) -> SchedulePr
 
 
 @payroll_api_router.post("/api/v1/contracts/{contract_id}/pay-now")
-async def api_pay_now(contract_id: str) -> Payout:
+async def api_pay_now(
+    contract_id: str,
+    pricing_mode: PricingMode | None = None,
+    manual_rate: float | None = None,
+) -> Payout:
     """Settle the next period immediately, whatever the calendar says.
 
     Covers both "run it now" (do not wait for the tick) and "pay it early",
@@ -312,12 +325,16 @@ async def api_pay_now(contract_id: str) -> Payout:
     Recorded in the ledger like any other payout, with the early-payment
     noted in its detail. Returns the ledger row, including a failed one:
     the caller wants to know *why* a manual payout did not land.
+
+    `pricing_mode`/`manual_rate` price this one payout differently without
+    editing the contract — for entering a payment that happened weeks ago at
+    a rate the operator already knows. They apply to this call only.
     """
     contract = await crud.get_contract(contract_id)
     if not contract:
         raise HTTPException(HTTPStatus.NOT_FOUND, "Contract not found.")
     try:
-        return await services.pay_now(contract)
+        return await services.pay_now(contract, pricing_mode, manual_rate)
     except services.LifecycleError as exc:
         raise HTTPException(HTTPStatus.CONFLICT, str(exc)) from exc