In the foreign exchange market, the exchange rates of two currencies appear in pairs. The base currency comes first, the target currency comes last, and the middle is separated by "/". When calculating the price of a pair of currencies, the benchmark currency is regarded as a constant and the target currency is an exchange rate variable.

Euro EUR is the benchmark currency relative to all other trading currencies, such as Euro/USD, Euro/GBP, Euro/CHF, Euro/JPY, Euro/CAD, etc.

The pound is the base currency of currencies other than the euro, such as pound/dollar, pound/Swiss franc, pound/Japanese yen and pound/Canadian dollar. Euro/GBP applies to Euro only.

The US dollar is the third largest benchmark currency, such as US dollar/Canadian dollar, US dollar/Japanese yen and US dollar/Swiss franc. The exceptions are euro and pound against dollar, euro against dollar and pound against dollar. .