Fat Cat Card: Kimchi Premium Cost on 1M Won Spent
Short answer: On a USDT card, the premium you pay to buy USDT with local currency is added to the card fees, and it is the same for every card. In the worked example below, a 4% premium costs ₩40,000 per ₩1,000,000 spent, while the gap between the best and worst card is only ₩4,500. Check the premium first, then the card.
Most USDT card comparisons argue about cashback. That ignores the biggest line in the bill.
Below is a calculation you can repeat with your own numbers. All card figures in it are invented round numbers, not Fat Cat Card rates, so the arithmetic is what matters.
What This Works Out
- What costs sit between your won and a USDT card payment?
- How do you add the premium to the card fees?
- Does the premium change which card is cheapest?
- Why does token cashback need a haircut?
- How do you run this on a real card?
What costs sit between your won and a USDT card payment?
Paying a Korean-won bill with a USDT card involves four cost layers: the premium when you buy USDT with won, the conversion from coin to dollars, the overseas payment fee at a won merchant, and cashback working against them. Fat Cat Card’s real-cost calculator page lists exactly these four and totals them into one percentage of the payment (fatcatcard.com, checked October 24, 2026).
The same page leaves four things out on purpose: ATM withdrawals, physical card issue and delivery fees, chain transfer fees and annual fees. It says Tron and Solana transfers are usually under one dollar. Those are one-off or situational, so they do not belong in a per-payment percentage.
When I checked the page, it also says ranges stay ranges. If a card publishes 0.5% to 1.75%, the calculator uses the range, not a midpoint. Good habit; copy it.
How do you add the premium to the card fees?
Add the local USDT premium, the conversion fee and the overseas payment fee, then subtract cashback; the result is the effective cost as a percentage of what you spent. Here are three made-up cards.
| Card (made-up) | Coin conversion | Overseas payment | Cashback | Cashback value lost on sale | Card layers net (no premium) |
|---|---|---|---|---|---|
| Card A | 0.5% | 0.6% | 1.0% | 0% | 0.10% |
| Card B | 1.0% | 0.0% | 0.5% | 0% | 0.50% |
| Card C | 0.5% | 0.6% | 1.5% | 30% | 0.05% |
The formula for each row is: premium + conversion + overseas fee − cashback (after any haircut). For Card A at a 2% premium that is 2 + 0.5 + 0.6 − 1.0 = 2.10%.
| Local USDT premium | Card A effective cost on ₩1,000,000 | Card B effective cost on ₩1,000,000 | Card C effective cost on ₩1,000,000 |
|---|---|---|---|
| 0% | 0.10% (₩1,000) | 0.50% (₩5,000) | 0.05% (₩500) |
| 1% | 1.10% (₩11,000) | 1.50% (₩15,000) | 1.05% (₩10,500) |
| 2% | 2.10% (₩21,000) | 2.50% (₩25,000) | 2.05% (₩20,500) |
| 3% | 3.10% (₩31,000) | 3.50% (₩35,000) | 3.05% (₩30,500) |
| 4% | 4.10% (₩41,000) | 4.50% (₩45,000) | 4.05% (₩40,500) |
Does the premium change which card is cheapest?
No. The premium is added to every card in the same amount, so it raises all costs together and never changes the ranking by itself. What it changes is how much any card can save you, and that is why it deserves its own look.
| What moves the cost | Range in this example | Won on ₩1,000,000 |
|---|---|---|
| Premium going from 0% to 4% | 4.00 points | ₩40,000 |
| Picking the best versus worst card at 0% premium | 0.45 points | ₩4,500 |
Here’s the part that surprises people. In this example the premium swing from 0% to 4% is bigger than the entire gap between the best and worst card. Shopping for a card while ignoring the premium is optimizing the small number.
Honestly, you cannot control it. You can only choose when to buy USDT, how much, and whether the number you see is worth paying today. The calculator page shows a live market value for the gap versus the dollar reference rate, which is the number to check before topping up.
Why does token cashback need a haircut?
Cashback paid in a token is valued at the price when you receive it, so if the token falls before you sell, the real cashback is smaller than the rate on the label. Fat Cat Card’s calculator page makes the same point: it notes some cards pay back in assets such as ETHFI, USDT or points rather than cash.
Card C in the example advertises the highest cashback, 1.5%. I applied a 30% loss in value by the time it is sold, which is a deliberate stress assumption and not a forecast. Its real cashback becomes 1.05%, and at a 0% premium its effective cost is 0.05%, against 0.10% for Card A.
Also watch the cap. Fat Cat Card’s page says a monthly spending cap can reorder the ranking, which is covered with numbers in Fat Cat Card: USDT Cashback Cap and Fees, Worked Out.
How do you run this on a real card?
To run this on a real card, copy its conversion fee, overseas fee, cashback rate and cap from the issuer’s official page, check today’s premium, then use the formula above. If the issuer publishes a range, calculate with both ends and keep both answers.
- Write down each fee with the date and the page you read it on.
- Check the local USDT premium against the dollar reference rate today.
- Compute the effective cost at the low and high end of any fee range.
- Test with a small top-up and compare the deduction with your sheet.
Compare USDT cards on Fat Cat Card
The same method is laid out as a checklist in How to Choose a Crypto Spending Card: 5-Question Table, and the application steps are in Fat Cat Card: Get a USDT Card and Top It Up Step by Step.
Not financial advice. Crypto cards carry issuer, regulatory and price risks, and fees and benefits vary by country, KYC and issuer policy. Do not load more than you can afford to lose.
Tips
- Check the premium before every top-up, not once.
- Keep a sheet with the date next to every fee.
- Treat token cashback as worth less than its label until you have sold it.
Warnings
- The cards in this example are invented; do not read them as real rates.
- A fee range is a range; do not average it away.
- Premium and fees change; yesterday’s sheet can be wrong today.
FAQ
What is the kimchi premium on a USDT card?
It is the amount by which USDT costs more in Korean won than the dollar reference rate suggests. Fat Cat Card’s calculator page says it adds to your effective cost on top of the card fees.
Does a higher cashback rate always mean a cheaper card?
No. A monthly cap, or cashback paid in a token that can lose value, can make a lower headline rate cheaper in practice.
What does the effective cost calculation leave out?
Fat Cat Card’s calculator excludes ATM withdrawals, physical card issue and delivery fees, chain transfer fees and annual fees, because they are one-off or situational rather than per-payment.
Sources
🔗 Related guides
Fact-checked based on public sources as of October 24, 2026.
