Foreign Exchange Rates Explained

A foreign exchange rate expresses the value of one currency relative to another. Learn how current rates, historical observations, currency pairs, and conversions are used in software and business workflows.

Explore the Forex API

Currency conversion

Currency conversion applies an exchange rate to an amount in one currency to calculate its value in another. See the conversion endpoint reference.

Current exchange rates

Current rates provide the latest available value for selected base and quote currencies. Browse the supported currency codes.

Historical exchange rates

Historical observations make it possible to value transactions on a past date and analyze how a currency pair changed over time. See the historical endpoint reference.

Rate changes

Comparing two dates shows the absolute and percentage movement in an exchange rate over a selected period. See the change endpoint reference.

How exchange-rate data is used

Applications use exchange-rate data to display localized prices, convert invoices, normalize reports, value historical transactions, and monitor currency exposure.

A base currency is the reference currency; quote currencies are valued relative to that base.
Current data supports operational pricing and conversion, while historical data supports reporting, reconciliation, and analysis.
Common base currencies include USD, EUR, GBP, JPY, and CAD, but international applications may need much broader coverage.
Refresh frequency, precision, available history, and supported pairs should be matched to the intended workflow.

Common data requirements

Current rates for localized prices and conversions
Historical rates for dated transactions and reporting
Hourly or OHLC observations for time-based analysis
Explicit base and quote currency selection

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