To exchange currencies between the currency balances on your account you can make a “balance exchange” order. For example, you can exchange $100 that you already have in your USD balance and put £80 into your GBP balance (the amounts will depend on the exchange rate at the time). All without paying in any extra money from your bank account.
On the website:
Sign in and then click the 'Exchange' option near the top right of the page:
You will then be able to choose to exchange from a currency you already have a balance in, into any of the other 14 available currencies.
On the mobile app
Please sign and press the '+' symbol near the bottom of the screen:
Then press the 'Move money' button at the top.
To exchange money on your card, please choose to move money from your Personal card to your personal card and press 'next'. From this screen, you can also exchange money on a Linked Card or move money between a personal card and Linked Card.
On the next screen, you'll be able to exchange from a currency you already have a balance in into any of the other 14 available currencies.