Currency Converter

How to use the currency converter

1. 1Enter the amount in the source currency; do not include commas or a currency symbol in the input box.
2. 2Select the source and target ISO 4217 currency codes, then confirm the currency names shown below them.
3. 3Read the converted amount together with the displayed rate and update timestamp.
4. 4For a payment or transfer, compare the result with the provider's quoted customer rate and fees.

Formula and worked example

With the current selections, the engine uses the next available EUR per USD. Therefore 100 USD × rate = 0 EUR. Both source rates come from the same USD-based response, so dividing them creates the USD/EUR cross-rate.

Rate source, timing and limitations

Rates are supplied by the ExchangeRate-API open-access endpoint and are reference rates, not a guaranteed bank, card, cash or remittance quote. The provider documents that this open endpoint updates once per day. OneCalcApp shows the timestamp returned by the feed; weekends, holidays and market closures can make the latest available reference older than the current clock time.

Real customer amounts may differ because of bid/ask spreads, service fees, card mark-ups, taxes and rounding. For a time-critical or regulated transaction, obtain an executable quote directly from the institution.

Rates by ExchangeRate-API — open endpoint documentation · Rate feed currently unavailable