Foreign-currency transactions can produce several different values for one commercial event: the amount on the supplier or customer document, the amount recorded by a payment provider and the sterling amount that eventually reaches or leaves the bank. A useful bookkeeping process preserves those values and their sources instead of trying to make every document show the same number.
Record the source currency first
Capture the currency and amount shown on the original invoice, receipt or sales document. Do not replace that source value with the sterling bank amount. Keeping the original commercial value visible helps a reviewer understand what was actually billed and provides a reference for later settlement checks.
Identify the payment route
Establish whether the transaction was settled directly from a bank account, through a card, payment platform or another route. Different providers can present conversion and settlement information differently. The payment evidence should be linked to the same transaction without assuming that the bank description contains the complete conversion detail.
Retain the rate evidence actually used
If the payment provider or bank supplies a conversion rate or a breakdown of the converted amount, preserve that information. Where the bookkeeping treatment requires a rate choice beyond what the transaction evidence establishes, the responsible accountant should determine the appropriate approach. The bookkeeper should not invent a rate simply to eliminate a difference.
Separate provider charges from conversion differences
A sterling settlement may differ from a simple currency conversion because the provider has applied a separate charge or another adjustment. Check the available statement or transaction detail before labelling the whole difference as exchange movement. If the components cannot be established, keep the difference visible for review.
Match refunds in both currencies
A foreign-currency refund may not produce the same sterling amount as the original payment. Connect the refund to the original transaction using supplier references and source-currency values where available. Do not treat a sterling difference by itself as evidence that the refund is incomplete.
Watch period boundaries
The invoice date, transaction date and settlement date can fall in different periods. Preserve those dates rather than moving the underlying commercial document merely to match the bank movement. Any period-end accounting judgement should be made from the relevant evidence by the person responsible for the accounts.
Keep multi-currency account transfers distinct
Where a client moves funds between its own currency accounts, identify both sides of the movement and any conversion evidence. This prevents the transfer from being mistaken for income or expenditure and helps expose any unsupported residual difference between the accounts.
Close with a source-to-sterling trail
The completed record should let a reviewer move from the original foreign-currency document through the payment or receipt evidence to the sterling movement recorded in the bank. Supported charges and differences should remain separately identifiable. That trail is more reliable than forcing all values to agree without showing how the conversion actually occurred.