Currency API how-to guides | exchangerate.dev

Each guide shows dated example numbers from one API response, a formula and a request to run. The rates are indicative mid-market figures; banks, cards and transfer services apply their own spreads and fees.

Get a free API key Run sample request

How-to guides

Follow the calculation step by step with the formula and dated example numbers, then run the API request.

Calculate a cross rate: Derive EUR to JPY from two USD quotes

More currency resources

Read guides and tutorials for more currency resources.

Use the historical date lookup or Excel currency conversion for currency calculations.

Questions

What does each guide include?

Each guide has a formula, dated example numbers from one API response and a request to run. Follow the calculation with those numbers, then use the request to make the API call.

Do requests need an API key?

An API key is optional for keyless access, which allows 10 requests a minute and 100 an hour per IP. Rates are 15 minutes late. Free API keys have 5,000 requests a month and 10 requests a minute.

How are currency pairs calculated?

The API quotes currencies against USD and derives other currency pairs through it. For an EUR base request for JPY, the API returns the derived rate and lists JPY in `derived_symbols`.

Can I use rates for settlement or trading?

Rates are indicative mid-market figures and are not for settlement or trading. Banks, cards and transfer services apply spreads and fees, so the amount paid out differs from the amount calculated with the API rate.