Debit-card currency conversion: charges to compare
Paying by UK debit card abroad can involve more than one cost: your bank’s foreign transaction charge, a cash-withdrawal fee, the card network exchange rate and, if you accept it, the merchant’s own dynamic currency conversion.
When a terminal asks whether to pay in pounds or the local currency, choosing the local currency usually avoids the merchant’s dynamic currency conversion. Your own bank may still charge a foreign transaction fee, so check the card tariff before travelling.
Separate the exchange rate from the bank fee
A card purchase can look fee-free while still costing more through the exchange rate. Some UK debit cards add a percentage foreign transaction fee; others do not. The card scheme converts the purchase unless the merchant offers to convert it into pounds first.
If you spend €200, the meaningful comparison is the final sterling amount debited, not just whether a separate £3 fee appears. A card with no explicit foreign-use fee can still produce a different sterling total from another card because the conversion timing and rate differ.
Practical check for this section: A €300 purchase offers a sterling price at the terminal as well as the option to pay in euros. Compare that record with the card provider’s foreign-transaction fee, the exchange rate used, any ATM fee and whether dynamic currency conversion is being offered by the merchant or machine. The point is to separate what you know from what you have only assumed. Compare the local-currency route with the quoted sterling conversion before accepting it. Treat the merchant conversion and your bank’s fee as separate cost layers.
Dynamic currency conversion is a separate choice
At foreign terminals and ATMs you may see 'Pay in GBP' alongside the local currency. Choosing pounds lets the merchant or ATM operator set the conversion rate. That convenience can carry a substantial markup. Choosing euros in France, dollars in the US or the relevant local currency normally leaves the conversion to your card issuer/network instead.
Example: an ATM offers to convert €300 at £1 = €1.10, making the sterling debit about £272.73 before other charges. If your card network would have converted at £1 = €1.16, the same €300 would be about £258.62. The difference is roughly £14.11 before any ATM or bank fee.
Put the decision into a small worksheet rather than relying on the headline. Use A €300 purchase offers a sterling price at the terminal as well as the option to pay in euros. as the test case and list the money at risk, the deadline or status, and the result of checking the card provider’s foreign-transaction fee, the exchange rate used, any ATM fee and whether dynamic currency conversion is being offered by the merchant or machine. Compare the local-currency route with the quoted sterling conversion before accepting it. Treat the merchant conversion and your bank’s fee as separate cost layers.
Cash withdrawals can carry an extra layer of charges
An overseas ATM can add its own usage fee, and your UK bank may add a cash-withdrawal fee or percentage charge. Those costs are separate from dynamic currency conversion. The ATM should show its own fee before you confirm, while your bank's tariff tells you what it adds.
Withdrawing one larger amount can sometimes reduce repeated fixed ATM charges, but carrying more cash has security risks. The better approach is to know your card's fee schedule and use reputable ATMs that disclose charges clearly.
Build the evidence file while the event is still fresh. For a case like A €300 purchase offers a sterling price at the terminal as well as the option to pay in euros., keep receipt showing the selected currency, settled card amount, provider tariff, ATM screen or merchant quote and the date of the exchange. That is more useful than sending dozens of unrelated screenshots. Compare the local-currency route with the quoted sterling conversion before accepting it. Treat the merchant conversion and your bank’s fee as separate cost layers.
Pending amounts can change before they settle
A foreign card transaction can first appear as a pending sterling estimate and later settle at a slightly different amount. Hotels, petrol stations and car-hire firms can also place temporary authorisation holds that are larger than the final purchase.
Keep the receipt in the local currency. If you later dispute the conversion, that receipt lets you compare the original purchase amount with the sterling amount and any separate fee on your statement.
Worked decision example: A €300 purchase offers a sterling price at the terminal as well as the option to pay in euros. Before acting, compare the best-case, expected and worst-case outcome using the card provider’s foreign-transaction fee, the exchange rate used, any ATM fee and whether dynamic currency conversion is being offered by the merchant or machine. If the action is reversible, record what should happen next and set a date to check it. Compare the local-currency route with the quoted sterling conversion before accepting it. Treat the merchant conversion and your bank’s fee as separate cost layers. This converts a vague banking problem into a sequence you can verify.
How to check a charge you do not recognise
Look at three lines of evidence: the merchant receipt, the bank statement and your card's foreign-use tariff. If the merchant converted the purchase into pounds without your agreement, raise that with the merchant and card issuer. If the bank applied a fee contrary to its published tariff, ask it to explain the calculation.
Do not describe every difference as 'a bad exchange rate'. State the local-currency amount, the sterling debit, the date and any separate charge. That gives the bank enough information to determine whether the issue was its fee, card-network conversion or merchant-provided currency conversion.
Set an escalation trigger instead of waiting indefinitely. For A €300 purchase offers a sterling price at the terminal as well as the option to pay in euros., decide in advance what result or deadline would make you contact the bank, provider or other organisation again. Keep receipt showing the selected currency, settled card amount, provider tariff, ATM screen or merchant quote and the date of the exchange. If the settled amount uses a currency choice you did not make, keep the receipt and statement and ask the bank or merchant to explain which conversion route was applied.
Compare the whole foreign-spend cost
A foreign card purchase can contain more than one cost: the exchange rate used, any non-sterling transaction fee, and sometimes a merchant's own currency-conversion offer. If a €200 purchase is converted by the merchant into pounds at a poor rate, choosing sterling can cost more even when the receipt makes the pound amount feel reassuringly certain. In many cases it is better to pay in the local currency and let your card provider perform the conversion, but check your own card's current fee terms first.
Before travelling, look at the tariff for purchases and cash withdrawals separately. A card that is cheap in shops can still be expensive at an ATM once provider fees and the machine operator's fee are combined. Keep one backup payment method in case the cheapest card is blocked or lost.
Sources and verification
James Whitmore - Head of Research
Abroad, always ask who is doing the conversion and who is charging the fee. “Pay in pounds” can sound safer, but it often hands the exchange-rate decision to the merchant or ATM operator.
MyBankAnswers uses official provider and UK regulatory sources wherever practical. Information is general and does not constitute financial advice.