Fat Cat Card: How to Pay a Foreign Online Store

A UK shop has the jacket you want, the checkout asks “Pay in GBP or USD?”, and you have a USDT card in hand. That one dropdown can swing the total by a few dollars before Black Friday even starts.

This worked example uses the KAST card, one of the USDT cards Fat Cat Card compares, and the fee table on KAST’s fees and conditions page updated October 22, 2026. Every scenario uses the free Standard tier. It’s a worked example, not financial advice.

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• What does KAST charge on a non-USD online order?
• What does a foreign order cost at different sizes?
• Should you pay in USD or the store’s currency?
• When does the monthly cashback cap change the math?
• How do you check your own order before paying?

What does KAST charge on a non-USD online order?

As of October 22, 2026, KAST charges a 0.5% to 1.75% foreign exchange fee on non-USD card purchases, plus $0.10 on non-USD transactions under $25, while USD card spend carries a 0% fee (KAST fees and conditions page).

KAST says the exact FX fee depends on your country of residence, where the transaction takes place, the card program, and the fee shown in the app before you confirm. That’s why every result below is a range, not one number.

When I checked the page, I noticed that KAST itself frames Standard as “up to 1%” net. That’s the 1.5% cashback minus the lowest 0.5% FX fee. At the top of the FX band, the net flips negative.

What does a foreign order cost at different sizes?

On a KAST Standard card, a non-USD online order worth $200 costs $1.00 to $3.50 in FX fees and earns $3.00 in cashback, so the net ranges from a $2.00 gain to a $0.50 loss depending on the FX rate KAST applies.

Worked from KAST’s fee page (updated Oct 22, 2026). Positive = you come out ahead; negative = net cost. Assumes the purchase is eligible for cashback and under the monthly cap.

Look at the $24 and $25 rows. One dollar of order value removes the $0.10 fee. If your basket sits just under $25 in the store’s currency, adding a small item you actually need can make the order cheaper per dollar.

Below $25, the fee stacks up fast on repeat buys. Ten separate $10 orders in a month cost $1.00 in small-order fees alone, before any FX.

Should you pay in USD or the store’s currency?

A KAST cardholder should pay a foreign store in its local currency unless the store’s own USD conversion costs less than the 0.5% to 1.75% FX fee KAST would charge, because choosing USD swaps KAST’s fee for the merchant’s rate and markup.

That offer to pay in your home currency has a name: dynamic currency conversion. Visa’s dynamic currency conversion page says the merchant must show the amount in both currencies, the exchange rate, and any added fees or markup, and must not choose on your behalf.

The 3% and 0.4% lines are examples to show the break-even, not rates any store is known to charge. Here’s the test: if the USD price divided by the local price implies a rate worse than the market rate by more than your KAST FX fee, pick the local currency.

I found that this is the step people skip at checkout. The USD price looks familiar, so it feels safer. It usually isn’t cheaper.

When does the monthly cashback cap change the math?

KAST Standard pays 1.5% USD cashback only on the first $2,000 of eligible spend each month, so a $2,500 month of foreign orders earns at most $30.00 in cashback while FX fees apply to the full $2,500.

Big holiday orders are where this bites. If one large foreign order would push you over $2,000 this month, it can make sense to place it on the 1st of next month instead. Honestly, only do that if the price will still be there.

How do you check your own order before paying?

Before paying a foreign online store with a KAST card, check the currency on the final checkout screen, the FX fee the KAST app shows, the order size against $25 and your month-to-date spend against $2,000.

1. Go to the store’s final payment page and note which currency you’re being charged in.
2. If it offers USD, write down both prices and work out the implied rate.
3. Check the fee the KAST app shows before you confirm. KAST says that number is the one that applies.
4. If the order is just under $25 in non-USD value, decide whether to combine it with another planned purchase.
5. Check your month-to-date spend. Over $2,000 on Standard, the cashback stops.
6. Top up enough balance first. A declined payment for insufficient balance costs $0.50.

If the item might go back, read our breakdown of Fat Cat Card: What a Refunded Card Purchase Really Costs before you order. Refunds on foreign-currency purchases don’t always land at the same value.

Tips

• Group small non-USD purchases into one order over $25 where it makes sense.
• Decline a USD offer at checkout when the implied rate is worse than your KAST FX fee.
• Save a screenshot of the currency choice screen in case you need to dispute a charge.
• Use the same check for foreign subscriptions; our guide to The Hidden 2% on Every Foreign Subscription You Pay (2026) covers recurring charges.

Warnings

• KAST’s FX fee depends on where you live and where the merchant is; the app shows the exact figure.
• Cashback is subject to eligibility, the monthly cap and KAST’s rewards terms.
• Fees and limits here are from KAST’s page updated October 22, 2026 and can change.
• This is a worked example, not financial advice.

FAQ

Does a KAST card charge an FX fee on a foreign store that bills in US dollars?

KAST’s fee page lists a 0% fee for card spend in USD and applies its 0.5% to 1.75% foreign exchange fee to non-USD transactions. If the foreign store’s checkout bills in USD, the store’s own conversion rate is what you pay instead.

Is the $0.10 small transaction fee charged on US-dollar purchases?

No. KAST’s fee page, updated October 22, 2026, lists the small transaction fee as 0% for USD and $0.10 for non-USD transactions under $25.

Does KAST cashback still count on foreign-currency purchases?

KAST’s fee page shows an illustrative net effect of up to 1% for Standard, which compares the 1.5% USD cashback against the FX fee. Cashback is subject to eligibility, the monthly cap and the rewards terms.

Sources

• KAST: What Are the Fees and Conditions for KAST Cards and Accounts? (updated Oct 22, 2026)
• Visa: Dynamic currency conversion

Next step: before your next foreign order, open the KAST app fee preview and run the five checks above. For trips rather than online orders, see Fat Cat Card: Compare Crypto Card FX Fees on a Euro Trip.

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Fact-checked against KAST’s fees page (October 22, 2026) and Visa’s DCC guidance as of October 30, 2026. Not financial advice.