How are fees different on coin-margined and USDT-margined futures?

The fee is calculated the same way on both — position value × fee rate, once when you open and once when you close — but it is paid in a different currency. On USDT-margined (linear) contracts the fee is in USDT. On coin-margined (inverse) contracts it is settled in the traded coin, and the position value itself is measured in coins: contracts × face value ÷ price. So the dollar cost of the same fee rises and falls with the coin price.

Two contract types

USDT-margined (linear): margin, profit and loss, and fees are all in USDT. A 10,000 USDT position at a 0.05% taker rate pays 10,000 × 0.05% in USDT to open, and the same again on the closing value.
Coin-margined (inverse): margin and PnL are in the coin — BTC for BTC contracts. Each contract has a face value in USD, and the fee is taken in the coin. OKX's fee rules state that the trading fee for crypto-margined perpetual and expiry futures is settled in the traded crypto.

Position value in an inverse contract

KuCoin's fee guide gives the formula for coin-margined contracts with a face value of 1 USD: position value = contracts × 1 ÷ price, in coins. Its example: 1,000 contracts at a price of 50,000 is a position of 0.02 BTC, and the fee is 0.02 BTC × the fee rate.

Two things follow from that:

The fee is in BTC, not dollars. If BTC rises after you pay it, the fee turns out to have cost more in dollars than it looked; if BTC falls, less. Either way your coin balance is what shrinks.
The percentage is not the difference. At the same rate, the fee as a share of the position is the same in both types. What changes is the currency you pay it in and how that currency moves.

See also fee currency in the glossary and how futures fees are calculated.

The rates can differ

An exchange can publish a separate fee schedule for coin-margined contracts. The rates in loweef's comparisons are each exchange's standard published futures rates, so before comparing, check whether your exchange lists different rates for its coin-margined products. Using a limit order that rests in the book moves a fill to the maker rate on either type (see maker vs taker fees).

Funding

Coin-margined perpetuals pay or receive funding too, and on these contracts it is settled in the coin. Delivery (expiry) contracts have no funding at all — see what a funding fee is.

What this means for a fee rebate

loweef pays rebates in USDT, calculated from the commission the exchange reports for your account. Whether coin-margined trades are part of that depends on the exchange's program conditions — don't assume they are, and check before you rely on it.

Which one to pick

Mostly not a fee question. The rate applies the same way to both; the choice is about which currency you want your margin, profit and loss — and fees — to be in.

Frequently asked questions

Are coin-margined futures cheaper?

Not by design. The fee is still position value × rate on opening and closing; what changes is that it's charged in the coin. Compare the exchange's published schedules for each contract type.

Why is my futures fee shown in BTC?

Because you traded a coin-margined (inverse) contract. On those contracts the fee is settled in the traded crypto, so its dollar value moves with the coin's price.

Do coin-margined trades count for a fee rebate?

It depends on the exchange's conditions. Rebates are calculated from the commission the exchange reports, and loweef pays them in USDT.