Foreign exchange: rates of exchange
A list of HMRC monthly exchange rates is published on GOV.UK.
The list gives spot rates at 31 March and 31 December, and average rates for the calendar and financial years, for all major currencies and most minor ones.
The exchange rates published on the HMRC website are London closing rates - that is to say, the average of the buying and selling prices for the currency on the London foreign exchange market at close of business on the relevant day.
The London closing rate is not an ‘official’ rate and businesses may use other exchange rates for tax purposes. There is more about this at BIM39515.