Every time money crosses a border, someone takes a slice. The trick is knowing how many slices there are — and which ones you can avoid.
The benchmark: the mid-market rate
Currencies trade globally at a buy price and a sell price. The midpoint is the mid-market rate — the rate you'll see in most currency-converter searches. Retail providers almost never give you exactly this rate; the question is how far off they are.
Layer 1: the spread (the hidden fee)
The spread is the gap between the mid-market rate and the rate you're actually given. An exchange office showing "0% commission" still makes money — through the spread. That's why comparing rates, not fees, is the only honest comparison.
Layer 2: foreign transaction fees
Many bank cards charge a foreign transaction fee — usually a percentage — on purchases in a foreign currency, or even on purchases in your own currency processed by a foreign merchant. It may appear as a separate line on your statement or be built into the converted amount.
Layer 3: ATM fees (two of them)
Withdrawing cash abroad can trigger:
- Your bank's fee for a foreign withdrawal (flat, percentage, or both), and
- The ATM operator's fee, which the machine should display before you confirm.
Fewer, larger withdrawals reduce flat fees — balanced against how much cash you're comfortable carrying.
Layer 4: dynamic currency conversion (the optional fee)
When a card machine or ATM offers to charge you in your home currency, that's dynamic currency conversion. The rate is set by the merchant's provider and is usually worse than your card network's. It's the one layer that's 100% avoidable: always choose the local currency.
If you're paying in Europe: the markup must be disclosed
EU Regulation 2019/518 forces transparency on currency conversion in the EU:
- Since 19 April 2020, card issuers and DCC providers must express their total conversion charges as a percentage markup over the European Central Bank's latest euro reference rate, before you pay.
- Since 19 April 2021, EU card issuers must send you an electronic message (such as an app notification or email) with that markup when you first pay in another EU currency.
So on EU card terminals and ATMs, the DCC screen should show a markup percentage. Read it. It's the clearest evidence of what "paying in your home currency" costs.
Putting it together
The table below shows where each cost appears. It's structural — actual percentages vary by provider, so always check your own bank's fee schedule.
| Method | Spread / rate markup | Explicit fee | Can you avoid it? |
|---|---|---|---|
| Card purchase, local currency | Network rate (+ any issuer markup) | Issuer FX fee, if any | Choose a no-FX-fee card |
| Card purchase, home currency (DCC) | Merchant provider's rate | Built into rate | Yes — always pick local currency |
| ATM withdrawal | Network rate (+ issuer markup) | Bank fee + ATM operator fee | Partly — pick fee-free ATMs, withdraw less often |
| Airport exchange counter | Often wide (reported ~14%+ over reference rates) | Sometimes | Mostly — exchange only what you need on arrival |
| City exchange office | Varies widely | Usually 'none' | Compare rates with mid-market |
Structural comparison. Airport figure: NerdWallet, September 2026. Your own costs depend on your bank and provider.
A worked example (illustrative numbers only)
Say you spend the equivalent of 100 units of your home currency abroad:
- At the mid-market rate, it costs you 100.
- With a card that adds a 3% foreign transaction fee, it costs about 103.
- If you accept DCC with a 5% worse rate on top of that card, you might pay around 108 — for the exact same coffee and museum ticket.
The percentages above are made up to show the maths. The principle isn't: each layer compounds.
Uncle's checklist
- Know the mid-market rate for your destination (write it down), and check the network rate on the Visa or Mastercard calculators.
- Use a card with no foreign transaction fee as your main card.
- Decline DCC — at shops, restaurants and ATMs.
- Use bank ATMs and check the operator fee screen.
- Exchange only small amounts at airports.