How to Convert Currency with Official ECB Exchange Rates
If you show a price in another currency, generate an invoice, or record a bookkeeping amount, you want a rate you can explain later. The European Central Bank publishes official euro reference rates on every TARGET business day, usually around 16:00 CET. Banks, accountants and plenty of apps use them.
What these rates are (and aren't)
They are reference rates, not a live bid/ask from a broker. You shouldn't use them to time a trade. You should use them when you need a public, dated, official number: "on 10 November 2026, 1 euro was 1.1214 US dollars, according to the ECB."
The ECB quotes everything against the euro. To go from USD to GBP you convert USD → EUR → GBP. The arithmetic is straightforward, and any honest API should say so.
Doing it yourself
The daily file is public XML:
https://www.ecb.europa.eu/stats/eurofxref/eurofxref-daily.xml
There's also a 90-day history file. If you ask for a Saturday, use the previous business day.
In an app
MintRates reads those ECB files, converts through the euro, and says on every response that these are official reference rates, not live quotes. It is being listed on RapidAPI.
bash
curl --request GET \
--url 'https://mintrates-currency-exchange-rates.p.rapidapi.com/convert?from=USD&to=EUR&amount=100' \
--header 'X-RapidAPI-Key: YOUR_KEY' \
--header 'X-RapidAPI-Host: mintrates-currency-exchange-rates.p.rapidapi.com'
You can also ask for /latest?base=USD or /historical?date=2026-10-15. About 30 currencies are included, whatever the ECB publishes. Docs: MintRates documentation. There's a free monthly allowance.
Make room for what matters: pick a rate you can cite, then get back to the work.
