Currency Calculator

Convert between world currencies at live exchange rates.

Forward contracts let importers and exporters fix a rate for a future date, and the gap between spot and forward reflects the interest-rate difference between the two currencies. Travel money carries the widest spread of any retail conversion.

The dollar is the world's reserve currency and one side of nearly 90% of foreign-exchange trades, so most conversions amount to a rate against the dollar. Spreads of 1-3% over the interbank rate are how banks and card issuers earn on the transaction.

Exchange rates are quoted in pairs, and the US dollar sits on one side of most of the world's trades, which is why a conversion is normally expressed against it. Card and counter rates include a spread of roughly 1-3% over the interbank rate, and a handful of currencies are pegged rather than floating.

The interbank figure shown here is the mid-market rate: it is the fairest comparison available, but it is not the rate a bank or card issuer will actually give you.

Rates respond to interest-rate expectations more than to trade balances, and a currency that looks weak against the dollar may be strong against its neighbour. The rate a card issuer applies on the day of settlement usually includes a markup of two to three percent.

Currency Calculator sits with the rest of the library's finance work, and it rests on the same foreign-exchange arithmetic the way a lender's disclosure or a bank statement does. Its answer is only as good as the assumptions standing behind it.

Money questions in America turn on the same few trade-offs: how long a balance is carried, what rate applies to it, and whether the money is being paid down or built up. Inflation sits behind all of them, since a figure that looks generous at today's prices buys less at tomorrow's, and comparisons across decades are made in real, inflation-adjusted terms.

American products also disclose their costs in prescribed ways, from the APR on a consumer loan to the annual percentage yield on a deposit account.