P/L is proceeds minus cost basis — fees included on both sides
Cost basis is what you actually paid to get in (price × amount, plus the entry fee). Proceeds is what you actually walked away with (price × amount, minus the exit fee). The difference between them is your real net profit or loss — not the naive “exit price minus entry price” that ignores fees eating into both ends.
Why the percentage matters as much as the dollar amount
A $500 profit means something very different on a $1,000 position than on a $50,000 one. The % figure here is P/L relative to your cost basis, which is the number that’s comparable across trades of different sizes.