Futures calculator

• A linear perpetual contract, with margin in USDT and isolated margin: if the position is liquidated, you lose the margin you put in and nothing else from your account.
• Liquidation comes when what's left of the margin drops to the maintenance margin. In a long, the price is entry × (1 − 1/leverage) / (1 − maintenance); in a short, entry × (1 + 1/leverage) / (1 + maintenance).
• It's an approximation. Each exchange uses its own tiered maintenance margin table (the percentage rises as the position grows), liquidates based on the mark price rather than the last price, and some reserve the closing fee inside the margin. That's why its liquidation price may not match this one exactly.
• The fee is charged on opening, on the notional, and on closing, on the position's value at that price. The funding rate isn't included; it's paid or received every few hours while the position stays open.

Because it uses its tiered table, the mark price and sometimes reserves the closing fee. The difference is usually small, but the figure that counts is the one your exchange shows before you confirm the order.

The first tier for your pair, found in the contract details. For major pairs like BTC and ETH against USDT, it's usually between 0.4 and 0.5 %; for the rest, and for large positions, it's higher.

You lose that position's margin, and the exchange usually keeps whatever is left as a liquidation fee. The rest of your balance is untouched. In cross margin, by contrast, your whole balance backs the position: liquidation comes later, but it can take much more.

PnL is what you win or lose in USDT. ROE is that PnL as a percentage of your margin: at 10x, a 1 % move is 10 % ROE, for or against you.