Settling up in a foreign currency — rates, fees, and not arguing over pennies
You get back from a trip, sit down to settle up, and it turns out the same dinner cost each of you slightly differently. Nobody’s lying — everyone simply paid at a different exchange rate.
Where the differences come from
Four mechanisms, often all at once:
Your bank’s rate on card payments. The bank converts at its own rate, typically with a 1–3 percent margin over the interbank rate.
DCC — conversion at the terminal. The card machine asks “pay in PLN or EUR?”. Choosing your home currency means the merchant does the conversion, at their own rate — almost always worse than your bank’s. Always choose the local currency. This is one of the simplest savings available while travelling, worth 3–7 percent.
Bureau de change or ATM. Exchange office rates range from good to terrible. ATMs add a withdrawal fee, sometimes at both ends.
When you paid. On a longer trip the rate simply moves. The same euro amount on Monday and Friday is a different amount at home.
The result: four people, four different “true” costs for the same thing.
How to settle the group
The key rule: convert everything once, at a single rate.
If you settle each expense at whatever rate the payer happened to get, you’ll get four answers to the same question and an argument that can’t be resolved — because everyone is right from their own point of view.
Instead, pick one rate for the whole trip. Simplest and easiest to defend:
- the central bank’s mid rate on your departure date — public, checkable, nobody’s;
- or a rate from the middle of the trip, if it was long.
Rate differences then become the private gain or loss of whoever paid — which is fair, since they chose the payment method.
In Paragonix the group stores an exchange rate, so all amounts convert consistently and nobody has to work it out separately. Organising trip settlements more broadly is covered in the group trips guide.
When not to bother
Some perspective: on a 40 euro expense, the difference between rates is a złoty or two. Working that out costs more energy than it’s worth.
Rates start to matter on accommodation, car hire and tickets — items in the hundreds, where 3 percent is a real amount. There it’s worth checking who paid how.
Three habits that save the most
- Always pay in the local currency — decline the terminal’s offer to convert.
- Withdraw larger amounts less often, if the withdrawal fee is fixed.
- Photograph the receipt immediately, with the local-currency amount on it. Reconstructing what dinner in Lisbon cost a week later is impossible — the receipt remembers.
The currency is read off the receipt automatically, so a photo taken on the spot is enough for everything to be converted later.