By Lindsey Olander
September 11, 2015
Credit: iStockphoto

In recent years, travelers have been given a choice by ATMs and merchants to select what’s called “dynamic currency conversion”: an option to convert the amount of your bill or cash withdrawal to your home currency on the spot—instead of your bank doing it later. The benefit is knowing right then exactly how much you’re spending in dollars, but the risk, says founder Brian Kelly, is overpaying because of a worse conversion rate, plus a fee for the service that is often undisclosed to the customer. “You could be adding up to seven percent to your purchase,” he says.

The final word: Always choose to be charged in the local currency, and use a credit card that waives all foreign transaction fees (read our recommendations here). To stay abreast of the most current rates, download Oanda’s Currency Converter app, which tracks the day’s rates for more than 190 currencies.