If you have a currency assigned to your card, charges will only be executed in the chosen currency. Read more about currency spending settings here. Otherwise -
Currency for the card payment is selected in the following order:
Revolut will auto-convert funds (fees may apply). Check this FAQ to learn more about currency conversion fees.
👉 Payment amount cannot be charged from several currency accounts at the same time, even if the total across wallets is enough.
👉 To avoid charges in a specific currency, keep a low balance or disable the currency account by tapping the three dots button below your balance and selecting 'hide'. Home currency cannot be deactivated.
If you were charged in a different currency than expected, it may be due to Dynamic Currency Conversion. Read more about DCC here.