Cards & currency
Why your card charged a different amount than the price tag
You paid 1,500 baht for dinner. The next morning your banking app said one thing, and four days later your statement said something else again. Nothing went wrong. The price you agreed to and the amount you were charged are decided on different days, at different rates, by different companies.
There are two separate events, not one
Tapping your card does not move money. It starts a chain with two distinct steps, and almost every surprise on a foreign statement lives in the gap between them.
- Authorisation happens in the restaurant, in seconds. Your bank confirms the money exists and places a hold for roughly the right amount. This is the number your banking app shows you as “pending”.
- Settlement happens when the merchant actually claims the money — typically one to three business days later, and longer across a weekend or a public holiday. This is the number that lands on your statement, and it replaces the hold entirely.
The exchange rate is applied at settlement, not at authorisation. So the rate that determines what you paid is the rate on a day you were not in the restaurant, and possibly not even in the country.
Three things move the number, and they stack
1. The network rate on the settlement date
Visa and Mastercard each publish their own rate, and they apply the one in force when the transaction clears. Buy something on a Friday evening and it may not clear until Tuesday — you get Tuesday's rate. Over a few days this is usually small change. During a volatile week it is not.
2. Your bank's foreign transaction fee
A separate charge added by your card issuer, commonly around 2–3% and distinct from the network's conversion itself. Some cards fold it into the displayed amount, some list it as its own line. Either way it is real money and it is not in the price you saw on the menu.
3. Dynamic currency conversion — the one you can refuse
When a card terminal or a hotel desk asks “would you like to be charged in your home currency?”, that is dynamic currency conversion. It lets the merchant's payment processor set the exchange rate instead of your card network — and their rate is essentially always worse. It is presented as a convenience because a familiar currency feels safer.
Always choose the local currency. This is the single easiest money you will save abroad, and it is the only one of these three you control.
Why hotel and car hire holds look alarming
Hotels, car rental desks and some fuel pumps deliberately authorise more than they expect to charge, to cover a minibar, a late return or a tank of petrol. A £300 hold against a £180 booking is normal practice, not a mistake or a scam.
The hold is released when the real amount settles, but the release is not instant — on a debit card it can sit against your available balance for days after you have checked out. If you are travelling on a debit card with a thin buffer, this is the mechanism most likely to leave you unexpectedly short.
What this means if you are tracking a budget
Here is the part most budgeting apps get wrong, because they were built for people who live in one country and spend in one currency: the day you spent and the day you were charged are not the same day.
If you record expenses by statement date, your spending gets shifted forward by a few days — which quietly ruins any per-day average, misattributes a purchase to the wrong city, and can push the last few days of a trip into a country you had already left. If you record by the date on the receipt but use today's exchange rate, the total drifts from what you were actually billed.
Getting this right means storing both: what the thing cost where you bought it, and what your bank actually took, whenever it eventually took it. That is exactly the split Kapunka keeps — a purchase has a date and a local amount, and the charge behind it carries its own date and its own rate.
The short version
Refuse dynamic currency conversion every time. Expect a 1–3 business day gap before the real number appears. Assume a foreign transaction fee unless you have confirmed your card has none. And treat a large hold from a hotel or rental desk as normal until a few days after checkout.
Related
Cards are the visible half of a travel budget. The invisible half is the cash in your pocket, which produces no statement at all — and the costs that a budget forgets entirely.