Paying in another currency: leaving room for conversion

Cards issued here hold a balance in US dollars. Many merchants, though, charge in their own currency: euros, pounds, Turkish lira, Indian rupees and dozens more. When they do, the dollar amount that leaves your card is only known at the moment of the charge, after a conversion. If the balance is tight, that conversion can decide whether the payment goes through or bounces. This guide explains what happens and how to leave the right amount of room.

How a foreign-currency charge works

When a merchant charges a card in a currency other than the card's own, a conversion happens somewhere along the payment chain. The merchant's price in its currency is turned into dollars using an exchange rate, and the resulting dollar amount is taken from the card.

Two things affect that dollar amount:

1. The exchange rate itself, which moves constantly.
2. Any margin or fee applied on top of the rate by the parties involved in the conversion.

You do not control either, but you can plan for both.

Where the uncertainty comes from

Rate movement

Exchange rates change through the day. A price that converts to 100 dollars this morning may convert to slightly more or less tomorrow. For a payment made shortly after you check, the movement is usually small; for a booking charged weeks later, it can be larger.

Conversion margins

Card payments rarely use the mid-market rate a search engine shows you; a margin is often built in. Some merchants and payment pages also offer to convert for you at checkout, at their own rate — a choice covered in more detail in our checkout articles.

Timing of the charge

Some merchants charge at the time of purchase; others authorize first and capture later, and the final conversion may happen at capture. Holds placed in a foreign currency can convert at one rate when placed and another when released.

How much room to leave

A practical approach:

1. Find the price in the merchant's currency, including taxes and fees.
2. Convert it with today's rate from a reputable source to get a baseline in dollars.
3. Add a few percent for margin and rate movement.
4. Add more if the charge will happen later, such as a booking paid at the property.

For most one-off purchases paid immediately, a few percent is enough. For future charges, add a bit more. Our guide on adding a buffer puts this alongside the other reasons to leave room.

A worked example

You are buying a course priced at 180 euros, charged immediately.

• Today's rate converts 180 euros to roughly 196 dollars (an illustrative figure).
• You add a few percent for margin: around 6 dollars.
• You round to a balance of 205 dollars.

At checkout, the actual charge lands a little above the baseline, well within the balance, and a small amount remains. Had you loaded exactly 196, the charge might have been declined.

Choosing between currencies at checkout

Some payment pages ask whether you want to pay in the merchant's currency or in US dollars. Pick dollars and the page does the conversion itself, at a rate it sets, and shows the dollar figure straight away. If you choose the merchant's currency, the conversion happens later in the payment chain.

Showing the dollar figure up front makes the balance easy to get right, but the rate offered may include a sizeable margin. Compare the dollar figure shown with your own conversion of the local price. If the difference is large, paying in the local currency and leaving a few percent of room is often the better deal.

Small amounts, small risks

For a 15-euro charge, even a generous margin is a dollar or two. For a 1,500-euro booking, a few percent is real money — both in the buffer you load and in the top-up charge on that buffer. That's why it's worth being a bit more careful with large foreign-currency purchases: check the rate the same day, avoid charging weeks later where you can, and size the margin rather than guessing.

Remember the card limits too: each card holds at least $10.00 and at most $5,000.00. Large foreign purchases near the top of that range leave little room for conversion. The keypad on the rates page shows what the larger balance will cost in total.

Refunds in another currency

If a merchant refunds a foreign-currency purchase, the refund is converted back into dollars, and the rate used then rarely matches the one from the day you paid. The amount that returns to your card can therefore differ slightly from what left it. This is normal and not something either side can fully control.

When the conversion leaves the card short

If a converted charge is larger than the card's available balance, the payment is declined and nothing is charged. The card keeps its balance. Because cards can't be reloaded, the fix is a fresh card loaded with enough for the charge plus a margin. Our guide to adding a buffer shows how big that margin should be.

A quick rule of thumb

If you don't want to work anything out, load the converted price plus a tenth for a single foreign purchase, and a little more if the shop adds tax at the end. It isn't precise, but it covers the usual gap between the rate you looked up and the rate the charge actually uses.

Quick answers

Is the card itself in dollars?

Yes. Balances are in US dollars, and charges in other currencies are converted to dollars when they are made.

Do you charge a conversion fee?

We do not take a fee per payment. Conversion margins, if any, are applied in the payment chain at the time of the charge.

Should I always choose to pay in dollars at checkout?

Not necessarily. The dollar figure is convenient but may include a margin. Compare it with your own conversion before choosing.

How much margin is enough?

A few percent for immediate charges, more for charges that happen later. Size it to the purchase.

Summary

Foreign-currency charges are converted to dollars at the moment of the charge, at a rate that may include a margin. Convert the price yourself, add a few percent, add more for later charges, and compare any dollar price offered at checkout before accepting it.