If you carry out a transaction using your card in a currency other than sterling, it'll be converted to sterling on the day the transaction is processed by our card scheme providers at a wholesale rate of exchange.
For an indication of that exchange rate, you can see the Visa wholesale rate of exchange at visaeurope.com/fxcalculator. (This is an "indication" as rates can change daily and transactions are processed when the retailer passes them on to the scheme provider, which is generally not on the same day the transaction took place.)
To compare the rates and charges for using your card abroad, please see our using your cards abroad page.