Feature
Live exchange rates, with the source on screen
A currency calculator is only as good as its rates. Calcurate shows where its rates came from and, for live rates, when they were published, and it keeps working when your connection does not.
Where do Calcurate’s exchange rates come from?
Calcurate tries three sources in order:
- ExchangeRate-API: daily mid-market rates covering all 15 currencies.
- European Central Bank reference rates via Frankfurter, published each working day. The ECB does not publish every currency (TWD, for example), so those fall back to the next step.
- Rates bundled with the app, if neither source can be reached and no rates were fetched in the last hour. The display then says
OFFLINE.
The display shows the source and date, for example LIVE 10 OCT, ECB 09 OCT or OFFLINE.
How fresh are the rates?
Rates are cached on your device for an hour, so the app opens instantly and works on patchy connections. Tap SYNC RATES to fetch fresh rates whenever you want. Live rates show their publish date on the display, so you can see how old they are.
Does it work offline?
Yes. In airplane mode, on a ferry or in a basement food court, the calculator keeps working. Rates fetched in the last hour are reused. After that, it switches to rates bundled with the app and shows OFFLINE. Bundled rates are fixed when the app version is released and can be out of date, so treat offline results as rough estimates and tap SYNC RATES when you are back online. Read more in our guide to offline currency conversion.
Mid-market rates, not bank rates
These are mid-market reference rates: the midpoint between buying and selling prices on the currency markets. Banks, card networks and exchange counters usually add a margin or fee on top. That makes the mid-market rate the right benchmark for checking what a card or exchange counter is really charging you. Learn why in what the mid-market rate is.
Calcurate is a calculator. It does not move money and it is not financial advice.
FAQ
Live exchange rates: common questions
How often does Calcurate update exchange rates?
The main source publishes rates once a day, and the ECB fallback each working day. Calcurate caches rates for an hour and you can tap SYNC RATES at any time to fetch the latest.
Are Calcurate rates the same as my bank’s rate?
Usually not. Calcurate shows mid-market reference rates. Banks and card providers often add a margin or fee, so the rate you are charged can be worse. Use the mid-market rate as a benchmark.
What does OFFLINE on the display mean?
It means Calcurate could not fetch rates and has none from the last hour, so it is using the rates bundled with the app. Results are still calculated, but the rates may be out of date. Tap SYNC RATES once you are online.
Related guides
What Is the Mid-Market Rate? (And Why You Rarely Get It)
The mid-market rate is the midpoint between buy and sell prices for a currency. Learn how it works, why banks add a spread, and how to compare quotes.
13 Jul 2026 · 6 min readMoney basicsHow Are Exchange Rates Determined? A Plain-English Guide
Exchange rates are set by supply and demand in currency markets, steered by central banks and pegs. See what moves rates and how reference rates work.
27 Jul 2026 · 7 min readTravel moneyOffline Currency Converter: How to Convert Without Data
An offline currency converter uses exchange rates saved on your phone. Learn how to prepare before a trip, how accurate stored rates are and what to check.
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Your next trip deserves a better calculator.
Mix currencies in one sum, see every conversion, and enjoy pressing the keys. Calcurate is on the App Store and Google Play.
