You’re at a card machine in a Lisbon shop, buying a pair of shoes for €80. The terminal blinks and asks a polite-looking question: would you like to pay in euros, or in your own pounds? One button says €80. The other says something friendlier, like £71.40, in your home currency, no mental arithmetic required. Most people press the pounds.
That instinct costs money almost every single time. The “pay in your home currency” option is a product called Dynamic Currency Conversion, and it exists for one reason: to move the exchange-rate markup off the bank and onto you, at a rate that is reliably worse than the one your card would have used.
I’ve watched this prompt skim a few extra pounds off transactions across about a dozen countries, and the pattern never changes. So let’s take it apart — what the machine is doing, why the “convenient” number is the expensive one, and the rare places the rule isn’t absolute.
What the machine is really asking
When you pay abroad, a conversion from local currency to your home currency has to happen somewhere. The only question is who does it and at what rate.
If you choose the local currency — euros, in the Lisbon example — the conversion happens later, inside the Visa or Mastercard network, at the wholesale interbank rate. That rate is close to the “real” mid-market number you’d see on a currency app, give or take a fraction of a percent.
If you choose your home currency, the merchant’s payment terminal does the conversion right there, on the spot, using a rate set by the company that supplied the terminal. They are not running a charity. The markup baked into that rate typically lands somewhere between 3% and 8%, and you are shown a tidy final figure that hides it completely.
Local currency = your card’s bank converts at a near-wholesale rate. Home currency = a third party converts on the spot and pockets a markup. Same purchase, different middleman.
A worked example, because the numbers do the arguing
Say the true mid-market rate is £0.86 to the euro. Your €80 shoes should cost about £68.80 before any card fee.
Choose euros, and a decent travel card converts near that rate. You’re charged roughly £68.80 to £69.30 — a rounding error away from fair.
Choose pounds via the terminal, and it quietly applies a worse rate of, say, £0.89. Now the shoes cost £71.20, presented as the helpful pre-converted total — around £2.40 gone on one small purchase. Scale that across a two-week trip of meals, taxis and tickets and the leakage adds up fast, exactly the slow drain I unpack in this breakdown of how one traveler cut a trip’s cost by forty percent without skipping anything.
Why the expensive option looks like the helpful one
This is the clever part, and the reason the trick survives. The home-currency option is engineered to feel like a favour.
It removes uncertainty. You see a number in pounds, recognise it, and know roughly whether it’s reasonable. The euro figure asks you to trust your card and do mental maths while a queue forms behind you.
So the worse deal is dressed as the considerate one. It’s the same psychology behind plenty of travel upsells — the friendly-looking default that nudges you toward the pricier path. I see the same move in airline checkout flows, which is partly why sorting the budget airlines worth their fine print from the ones that aren’t comes down to spotting the defaults before you tap “confirm”.
It’s not only card machines
The same prompt appears at foreign ATMs (“withdraw with conversion?”), in hotel checkout, and increasingly in online stores that detect your card’s country. Anywhere a screen offers to “lock in” your home-currency price, the markup mechanism is identical.
The myth: “but the locked-in rate protects me”
The most common defence of DCC is that it shields you from exchange-rate swings. You see the exact pound figure now, so there’s no nasty surprise on your statement later.
This is technically true and practically irrelevant. The rate moves by tenths of a percent over the day or two before your transaction settles. The DCC markup is several whole percent, charged up front. You are paying a guaranteed 3–8% to insure yourself against a risk worth a fraction of one percent.
Nobody buys insurance that costs more than the thing it protects. That’s the whole myth: a real but trivial benefit used to justify a much larger, certain cost.
Some terminals don’t ask out loud — they default to home currency and let the cashier hit accept. If your receipt shows your home currency plus a tiny line reading “conversion rate” or “DCC”, you were charged the markup. You can usually ask for it to be voided and redone in local currency before you leave.
How to refuse it cleanly, every time
The defence is simple and works almost everywhere.
- Always choose the local currency. Euros in Portugal, baht in Thailand, yen in Japan. If the screen lists both, pick the one that matches where your feet are.
- Say it out loud at the counter. “In euros, please” before they hand you the terminal heads off a pre-selected home-currency charge.
- Check the receipt. If it converted to your home currency anyway, ask for a reversal. Most staff have seen this and will fix it.
- Pair it with the right card. Refusing DCC only pays off if your card then converts cheaply — a no-foreign-fee card does the rest of the work.
If a foreign payment screen ever shows you a price in your own currency, treat it as a red flag, not a courtesy. The friendlier the number looks, the more likely it carries a markup. Choosing local currency is the rare money-saving move with no downside and no effort.
The rare cases where it’s a coin toss
I said “almost always”, and the qualifier earns its place. There are narrow situations where local currency isn’t an automatic win.
The first is if your own card is genuinely terrible — an old debit card charging a fat foreign-transaction fee plus a poor in-house rate. Against a really bad card, a DCC markup is sometimes a wash. The fix isn’t to embrace DCC; it’s to stop carrying the bad card.
The second is expense claims, where you may want the exact home-currency figure for reimbursement and the small premium is somebody else’s problem. Even then, know you’re paying for tidiness.
Beyond those, the answer is local currency. The same scepticism applies to “for tourists” pricing generally — the convenient option is rarely the cheap one, a theme I dig into when listing the tourist traps that charge double for the same experience.
“Pay in your home currency” lets a payment terminal convert at a marked-up rate instead of your card’s near-wholesale one. The convenience is real; so is the 3–8% cost. Choose local currency, carry a low-fee card, and check your receipts.
Does choosing local currency cost more in card fees than DCC saves?
Almost never. A typical DCC markup is 3–8%. Your card’s own foreign-transaction fee, if it charges one, is usually 0–3% on top of a near-wholesale rate. Even a mediocre card converting in local currency tends to beat the terminal, and a no-fee travel card wins comfortably.
What if the cashier already pressed my home currency before I noticed?
Ask politely for the transaction to be voided and re-run in the local currency. It’s a routine fix and most staff have done it before. If the payment has fully settled, your card issuer can sometimes help, though that’s slower and less reliable than catching it at the counter.
Does this apply to cash withdrawals at foreign ATMs too?
Yes, and it’s the same trap. When an ATM offers to convert “with a guaranteed rate” or shows your withdrawal in your home currency, decline the conversion and choose to be charged in the local currency. The machine’s rate carries the same markup as a shop terminal’s.
None of this requires an app, a spreadsheet, or any cleverness at the till. It’s one button, pressed correctly, a few times a day. Get into the habit of choosing local currency and checking the receipt, and you’ll quietly keep a slice of every foreign purchase that the terminal was hoping to take. Press the friendly-looking button, and you hand it over with a smile.
