Currency Converter

Convert currencies with daily reference rates

Enter an amount, choose the source and target currencies, and the converted value appears immediately. The exact reference rate and its effective date stay visible beside the answer, so the result never looks more current or precise than its source.

Use the swap button to reverse the pair without re-entering the amount. The settings are stored in the page address, which means a particular amount and pair can be bookmarked or shared.

Where the rates come from

Exchange-rate data comes from Frankfurter, an open-source service that aggregates rates published by central banks and other official institutions. Its current dataset covers more than 150 active currencies and currency-like units.

These are daily reference rates rather than second-by-second trading prices. Some currencies update every working day while others publish less frequently. Each result therefore shows the date of the older side of the pair, which is the honest date for the complete conversion.

Fetched once and saved on Isobj

Visitors do not contact Frankfurter directly. Once a day, WordPress downloads one complete EUR-based rate table plus the currency names and stores the normalized result in its own options table. The public converter reads that saved copy through an Isobj REST endpoint.

This design makes changing amounts and currencies instant, avoids exposing every visitor to a third-party request, and prevents a popular page from multiplying into thousands of upstream API calls. If a scheduled refresh fails, the last complete table remains available while WordPress retries; a partial response never replaces good data.

How cross-currency conversion works

The saved table records how many units of each currency equal one euro. A direct table for every possible pair would grow quadratically and duplicate the same information, so the converter derives any pair from the common base.

For a source currency S and target currency T:

pair rate = (EUR → T) ÷ (EUR → S)
converted amount = amount × pair rate

If one euro equals 1.14 US dollars and 0.85 British pounds, one dollar equals 0.85 ÷ 1.14, or about 0.7456 pounds. The intermediate ratio is kept at full floating-point precision and only the displayed answer is rounded.

Reference rate versus the rate you receive

A neutral reference rate is useful for estimates and comparisons, but it is not a promise from a bank or money-transfer service. Retail providers make money through an explicit fee, a less favorable exchange rate, or both. Card networks may also choose a different daily fixing or apply the rate when a transaction settles rather than when it is authorized.

For a real transfer, compare the final destination amount after every fee—not only the advertised exchange rate. For tax, financial reporting or trading, use the particular authority and timestamp required for that purpose.

Weekends, holidays and different dates

Central banks publish on working days. A conversion on Sunday will normally use Friday’s latest available data, and a national holiday can leave one currency a day behind another. That is expected rather than a failed update.

The converter chooses the older date of the two currency legs for its label. If USD has a Monday observation and another currency still has Friday’s, the pair is shown as Friday—not Monday—because both numbers were last known together on the older date.

Privacy and caching

The amount and selected currencies are ordinary calculator settings; the arithmetic happens entirely in the browser after the saved table loads. Frankfurter receives one scheduled server refresh for the whole site, not a request containing each visitor’s amount or pair.

The cached database record is deliberately non-autoloaded, so a large currency table is read only for the exchange-rate endpoint instead of being loaded into memory on every unrelated WordPress page.

Frequently asked questions

How current are the exchange rates?

The Isobj server refreshes its complete rate table once a day. Each conversion shows the date of the older currency leg, because different central banks can publish on different working days. Weekends and public holidays therefore continue using the latest available reference rate.

Where do the rates come from?

The rate table comes from Frankfurter, an open-source exchange-rate service that aggregates daily data from central banks and official institutions. Isobj downloads one EUR-based table and stores it in WordPress; visitors do not contact the upstream service.

Why is my bank or card rate different?

These are reference rates, not retail quotes. A bank, card network, exchange bureau or transfer service normally adds a spread, fee or both. The amount that actually reaches an account can therefore be lower than the neutral conversion shown here.

How are two non-euro currencies converted?

The saved table expresses every currency against EUR. To convert USD to GBP, for example, the tool divides the EUR-to-GBP rate by the EUR-to-USD rate, then multiplies by the amount. That cross-rate is mathematically equivalent to converting through EUR without rounding the intermediate value.

Are these rates suitable for trading or accounting?

They are suitable for estimates, comparisons and general informational use. Trading, tax filings and formal accounting may require a specific provider, timestamp or authority-prescribed rate. Use the source required for that purpose rather than a general blended reference rate.

Why can two currencies have different rate dates?

Frankfurter combines data from many institutions, each with its own publication calendar. A market holiday in one country can leave that currency on Friday's rate while another has a Monday update. The converter uses and displays the older date so it never overstates the freshness of the pair.

Does changing the amount make another API request?

No. WordPress fetches and persists one complete table server-side each day. The browser downloads that cached table from Isobj once, and every amount change, currency change and swap is calculated locally from the same data.