Currency conversion guides
Understand the number behind a conversion. These guides explain the arithmetic, rate dates, and common differences between an estimate and an actual payment.
Start with your question
Why does my card charge differ?
Separate reference rates, processing dates, and card fees with a worked example.
How much does conversion cost?
Calculate percentage fees, fixed charges, and the effective rate of a quote.
How do I prepare for offline travel?
Sync your currencies, test your setup, and recognize the limits of saved rates.
How do I add expenses in different currencies?
Convert to a common unit before adding a travel or project budget.
Put the formulas to work
Enter a quote in the fee calculator, compare and total costs in the multi-currency calculator, or explore the USD/EUR and EUR/TRY pair pages.
Check the source before using a number
Examples in these guides use illustrative rates, not current quotes. The web converter shows reference data for quick estimates. Read our methodology to understand the feed and update timing, or about Flexchange for product information and corrections.