What is Dynamic Currency Conversion — and why should you always say no?

You're at a hotel in Thailand. The card machine asks: 'Would you like to pay £87.40 or 3,800 THB?' The pounds option feels reassuring — you know where you are. It's also a trap. Dynamic Currency Conversion (DCC) lets merchants apply their own exchange rate, which is almost always 3–8% worse than what your bank would use.

What DCC actually is

Dynamic Currency Conversion is a service offered by merchants and ATM operators that converts your transaction from the local currency to your home currency at the point of sale. Instead of your bank doing the conversion at their rate, the merchant does it at theirs. In theory, it gives you certainty. In practice, the merchant's rate includes a large markup — typically 3–8% above the mid-market rate.

Where you'll encounter it

DCC is offered by ATMs (especially in tourist areas), hotel check-outs, restaurants in tourist zones, and some airport shops. ATMs in Thailand, Europe, and Southeast Asia are particularly aggressive about it. Some ATMs present DCC as the only clear option and make the 'pay in local currency' choice harder to find. Read every screen carefully before confirming.

How much it costs

On a £500 hotel bill, choosing DCC at 5% markup costs you £25 extra. On a 10-day trip with £2,000 of card spend, the DCC trap can cost £60–160 depending on how aggressively the merchants price it. This is on top of any foreign transaction fee your card already charges — meaning some travellers pay double.

How to always avoid it

The rule is simple and without exception: always choose to pay in the local currency. At an ATM, choose 'continue without conversion' or 'pay in local currency'. At a card terminal, press 'no' or choose the local currency amount. At a hotel, tell the front desk you'll pay in the local currency. If the terminal has already processed DCC, ask for it to be voided and reprocessed in local currency — most merchants will do this.

DCC vs your bank's conversion: why local currency always wins

When you pay in local currency, your card issuer converts at their rate. With a zero-forex card like Wise or Starling, that rate is at or within 0.1–0.3% of the mid-market rate. Even with a standard bank card adding 2.75%, you're still better off than DCC's 5–8% markup. The merchant's conversion is never in your favour — it exists solely to earn the merchant and their payment processor additional revenue.

The legal position

DCC is legal in most jurisdictions. The EU has regulations requiring DCC rates to be disclosed (Regulation 2019/518), but enforcement is inconsistent. In Thailand, UAE, and most Asian countries, there are no restrictions. Visa and Mastercard both technically require merchants to give customers the choice — but compliance varies widely. Your best protection is simply knowing the rule: always local currency, always.

Key takeaways