Use the exchange-rate source and date required by your accounting and tax policy, apply it consistently, and save the rate with the invoice. For ordinary bookkeeping, the transaction-date rate is the common starting point. Tax authorities may prescribe a different approved source or period.
There is no single worldwide invoice rate. A bank rate, central-bank reference, card-network rate and accounting-provider feed can all be valid for different purposes and still produce different numbers.
The decision in four questions
- What currency is legally due? That is the transaction currency shown on the invoice.
- What is your bookkeeping currency? The foreign receivable must be translated into it.
- Does the tax authority prescribe a source or date? Follow that rule for the tax record.
- What source does your accounting policy use? Apply it consistently to comparable transactions.
Rate dates compared
| Date | Use | Main caution |
|---|---|---|
| Invoice or transaction date | Initial revenue and receivable | May differ from a tax point defined by local law |
| Supply date | Required where the tax point follows delivery | Not always the invoice date |
| Period average | High-volume similar transactions where permitted | Not suitable during sharp movement or for material one-off items |
| Payment date | Value used to settle the receivable | Does not normally rewrite original revenue |
A worked example
A business with EUR books issues an invoice for USD 8,000. Its documented invoice-date rate is 0.92 EUR per USD, so the receivable is EUR 7,360.
Payment arrives later when the gross settlement converts to EUR 7,440. The processor deducts EUR 40 and deposits EUR 7,400.
| Entry | Amount |
|---|---|
| Original receivable | EUR 7,360 |
| Gross settlement value | EUR 7,440 |
| Realized exchange gain | EUR 80 |
| Processor fee | EUR 40 |
| Cash received | EUR 7,400 |
The fee is not an exchange loss and the revenue is not EUR 7,400. Keeping the three pieces separate makes gross margin and payment-gateway costs visible.
Which source to choose
- Official reference rate: strong for tax or policy consistency where recognized.
- Accounting feed: convenient when the source and timestamp are retained.
- Bank or processor rate: correct for the actual cash settlement, but it may include a spread.
- Contract rate: valid when both parties agree a fixed conversion method, subject to local rules.
Do not shop among sources after seeing which gives the preferred result. Consistency is the control. Document the provider, timestamp, currency direction and whether the quoted rate must be inverted.
Common mistakes
Using today’s rate on an old invoice
That rewrites the original transaction instead of recording the later movement.
Mixing direct and inverse quotes
EUR per USD is not USD per EUR. Store the currency pair as well as the number.
Calling fees an exchange loss
The spread may be embedded in the rate, but an explicit processor fee belongs in a fee account.
Ignoring tax conversion
A tax return may require an approved rate that differs from the commercial settlement rate. Confirm the local rule.
Using Invoice Crowd
Multi-currency invoicing stores the transaction currency while reporting in the business base currency. Record the source and date behind the rate so the value can be reproduced. If a backdated document uses today’s rate, the workflow warns about it, which is a prompt to confirm rather than an invitation to ignore policy.
Frequently asked questions
Should I use the invoice-date or payment-date exchange rate?
Use the policy or local rule for the invoice date to record the original receivable. Use the payment-date settlement value to clear it, with the difference recorded as realized foreign-exchange gain or loss.
Can I use a monthly average exchange rate?
Only where your accounting and tax rules allow it and the average reasonably represents the transactions. It is weaker for material one-off items or periods with sharp currency movement.
Is the bank rate the official invoice rate?
Not automatically. It is the actual settlement rate for the cash received and may include a spread. Tax or accounting policy may require a separate official or documented source for the original transaction.
Where should payment processor fees be recorded?
Separately as fees or payment-processing expense. Do not hide an explicit fee inside revenue or foreign-exchange gain and loss.
What rate evidence should I retain?
The provider, date and time, currency pair, rate direction, quoted rate, and any local rule or policy that selected it. A screenshot or machine receipt is useful for material transactions.
Can I change the rate after sending the invoice?
Correct a genuine error through a traceable process, but do not change the original rate merely because the currency moved. The later movement belongs in exchange gain or loss.
