Fat Cat Card: How to Split a Group Bill With KAST Tag

Somebody always ends up holding the whole bill. A hotel deposit, a long dinner, a rental car. Then the reminders start.

KAST has a built-in way to settle up, called KAST Tag. It’s free between KAST users. But who pays the bill in the first place changes how much cashback the group gets, and that part is rarely worked out.

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The numbers below come from KAST’s fees and conditions page, updated October 22, 2026. Every scenario uses the Standard tier, the free one. This is a worked example, not financial advice.

Contents

• How does KAST Tag work for paying someone back?
• Who should pay a $2,400 group bill?
• What changes when the bill is in euros or another currency?
• Does splitting a small bill cost extra?
• What if someone in the group isn’t on KAST?
• A settle-up routine for the trip

How does KAST Tag work for paying someone back?

KAST Tag sends money from one KAST account to another for free and instantly, up to $10,000 a day and 5 transfers a day, according to KAST’s fee page updated October 22, 2026.

The sender needs only the recipient’s KAST Tag, email or phone number. No wallet address, no network choice.

When I checked the limits, I noticed that the 5-a-day cap applies to transfers, not people. If you’re the one refunding six friends at once, you’ll hit it.

Who should pay a $2,400 group bill?

For a $2,400 USD bill split four ways on Standard KAST cards, having each person pay their own $600 earns $36 in total cashback, while one person paying the whole bill earns at most $30, because Standard cashback stops at the first $2,000 of spend each month.

KAST’s fee page lists Standard cashback as 1.5% on the first $2,000 a month. Here’s how that plays out for a hotel bill of $2,400 shared by four people:

When I compared the rows, I found that the gap is small on a fresh month and large on a busy one. $30 versus $36 is barely worth an argument. $7.50 versus $36 is.

So the rule of thumb is simple. Let the person with the most unused cap room pay. If nobody has room, pay separately.

Premium and Private tiers have much higher caps, $10,000 and $40,000 a month per the same page, so a Premium member can usually carry the whole bill without losing cashback. Whether Premium is worth its $1,000 a year is a separate sum, covered in Fat Cat Card: How to Tell if KAST Premium Pays Off.

What changes when the bill is in euros or another currency?

A non-USD bill paid on a KAST card carries a foreign exchange fee of 0.5% to 1.75%, depending on the country of residence, where the transaction happens and the card program, according to KAST’s fee page.

That fee applies to whoever pays, so splitting doesn’t avoid it. What it does is eat into the cashback. Take the same $2,400 bill, priced in euros, paid by one person on a fresh month:

At the top FX rate, the one paying is $12 down while the group saves nothing. Spread that fee across the group when you settle up, not just the bill.

Check your own rate in the KAST app before paying. The page says the app shows the fee before you confirm.

Does splitting a small bill cost extra?

Splitting a small non-USD bill into separate card payments can add a $0.10 fee to each payment under $25, because KAST’s fee page lists a $0.10 small transaction fee on non-USD transactions under $25.

An €80 dinner for four, paid separately at about €20 each, means four payments under $25. That’s $0.40 in small-transaction fees for the table. Paid by one person, it’s one payment over $25 and no small-transaction fee.

Honestly, $0.40 won’t ruin anyone’s night. But on a two-week trip with daily coffees and snacks split four ways, it adds up quietly. For small bills, one payer and a Tag repayment later is the cleaner option.

What if someone in the group isn’t on KAST?

A friend without a KAST account cannot use KAST Tag and has to repay by sending supported stablecoins to your KAST deposit address, which KAST says it doesn’t charge for, though blockchain network fees may apply on the sending side.

Going the other way costs more. If you owe them, you’d withdraw on-chain, and the flat part of the fee matters most on small amounts. Sending $50 by Arbitrum costs $0.25 under KAST’s listed formula. By Ethereum, $6.05.

Our guide to Fat Cat Card: How to Move Leftover USDT Off Your Card works through those withdrawal costs network by network.

A settle-up routine for the trip

1. Before the trip, compare cap room. Whoever has spent least this month pays the big bills.
2. Check the FX fee in the app for the destination currency.
3. For big non-USD bills, agree to split the FX fee along with the bill.
4. For small bills, let one person pay and log it.
5. Settle up by KAST Tag, with each person sending their own share. That keeps everyone under the 5-a-day limit.
6. Keep the Tag transfer records. They’re your receipts if anyone asks later.

Cap timing across a month is its own topic. See Fat Cat Card: Time a Big Purchase Around Cashback Caps for that.

Tips

• Ask each person to send their own Tag repayment instead of one person collecting and redistributing.
• If one person’s cap is already used up, they should not be the default payer.
• Use the app’s fee preview on the first non-USD payment of the trip.
• Settle up the same day. Tag transfers are instant, so there’s no reason to wait.

Warnings

• Cashback is subject to eligibility, monthly caps, region and transaction type, per KAST’s page.
• KAST Tag only works between KAST users.
• The FX fee range of 0.5% to 1.75% depends on your residence and card program.
• Fees and limits are from KAST’s page updated October 22, 2026 and can change. This is not financial advice.

FAQ

Is there a fee to send money with KAST Tag?

No. KAST’s fee page, updated October 22, 2026, lists the KAST Tag transfer fee as free and the processing time as instant, with a limit of $10,000 a day and up to 5 transfers per day.

Can a friend without a KAST account pay me back through KAST Tag?

No. KAST Tag sends funds between KAST users using a KAST Tag, email or phone number. A friend outside KAST would have to send supported stablecoins to your deposit address, which KAST does not charge for, though the sending network may.

Does splitting the bill change the FX fee?

Not in percentage terms. KAST’s fee page lists a 0.5% to 1.75% foreign exchange fee on non-USD card spend whoever pays, but four separate non-USD payments under $25 each would add a $0.10 small transaction fee per payment.

Sources

• KAST: What Are the Fees and Conditions for KAST Cards and Accounts? (updated October 22, 2026)
• KAST: Terms and Conditions of Service

Next step: before the next shared bill, check whose cap has the most room this month, and let that person pay.

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Fact-checked against KAST’s fees and conditions page as of October 30, 2026. Scenarios are hypothetical worked examples.