Profit and loss calculations are based on the contract’s collateral. For instance, a USDT-margined contract will be denominated in USDT.
Do note that unrealized Profit and Loss are calculated based on the Mark Price, while realized Profit and Loss are calculated based on the final trade price.
Profit and Loss calculations for USDT-margined contracts (BTCUSDT)
Assume you purchase (long) 10,000 USDT worth of BTC-USDT perpetual contracts at 50,000 USDT. The price increases and you exit at 55,000 USDT. Your PNL will be:
PNL = Position Size * (Futures Mark Price - Futures Entry Price) * Direction
Size = 10,000 / 50,000 = 0.2 btc
Direction=1 when you have a long position and Direction = -1 when you have a short position
PNL = 0.2 * (55,000 -50,000) *1 = 1,000 usdt
Assume you sold (short) 10,000 USDT worth of BTCUSDT perpetual contracts at 50,000 USDT. The price decreases and you exit at 45,000 USDT. Your PNL will be:
PNL = Position Size * (Futures Mark Price - Futures Entry Price) * Direction
Size = 10,000 / 50,000 = 0.2 btc
Direction = 1 when you have a long position and Direction = -1 when you have a short position
PNL = 0.2 * (45,000 -50,000) * -1 = 1,000 usdt
How to calculate Unrealized PNL and ROE%
USDT-Margined Perpetual Contracts
Unrealized PNL = position size * Direction * (mark price - entry price)
ROE% = Unrealized PNL / entry margin = ( ( mark Price - entry Price ) * Direction * position size ) / （position size * mark_price* IMR）
*IMR = 1 / Leverage
Direction = 1 when you have a long position and Direction = -1 when you have a short position