How we calculate
The formulas behind every result, where the exchange data comes from, and what an estimate cannot include.
Liquidation price, isolated margin
A USDT-margined perpetual is liquidated where the margin plus the unrealised result equals the maintenance margin. With size q in coins, entry E, margin M, the tier's maintenance-margin rate r and its maintenance amount d:
long: P = (q × E − M − d) / (q × (1 − r))
short: P = (q × E + M + d) / (q × (1 + r))The margin is what you enter; the size is margin × leverage ÷ entry. The maintenance amount (a deduction some exchanges publish per tier) is used where the exchange states it; where it does not, the whole position is charged at the tier rate.
Choosing the tier
The tier is the first one whose limit is at or above the position. Most exchanges state the limit as a position value in USDT; OKX and MEXC state it in coins, so for those the size in coins is compared. A position larger than the last tier uses the last tier, and the page says so.
Where the tiers come from
From each exchange's own published tier or risk-limit table, read automatically about twice a day. Where an exchange publishes no table that can be read without an account, its tiers are kept by hand from the exchange's own page, with a link and the date they were checked. Where neither exists, that exchange shows no liquidation price rather than a guess.
Funding
Funding rates and mark prices are read from each exchange every few minutes. The funding interval is the exchange's own, per pair; where an exchange does not state it, nothing that depends on it is computed. The price filled into the calculators is the middle of the mark prices the exchanges report.
Cross margin
With one position, the free balance is added to the position's margin. With several, the cross-margin calculator works out each position's price if only that coin moves and the others stay at their entry, which is an estimate because coins move together.
What is left out
- The estimated closing fee some exchanges set aside, which moves the real liquidation a little closer.
- The difference between the mark price and the last price.
- Funding paid while the position is open, except where the calculator shows it.
- Your fee level: fees are an input, because they depend on your account.