Exchange fee schedules quote a percentage; your P&L pays dollars. Converting between the two precisely — including the details most traders hand-wave — takes four short formulas. Master them once and every trade you take has a known cost and a known breakeven before you click.
Formula 1: the fee per leg
Fee = notional × fee rate. The crucial word is *notional* — the full position size, not your margin. A $10,000 position at 0.05% taker costs $5 to open whether you used 1x or 50x leverage. (What leverage changes is how big that $5 is *relative to your capital* — see How Leverage Changes Your Trading Costs.)
Formula 2: the round trip
You pay on entry and on exit, and the exit leg is charged on the exit notional, which has moved with price:
- Entry fee = size × rate
- Exit fee = size × (exit price ÷ entry price) × rate
- Round trip ≈ 2 × size × rate, plus a sliver more if the trade won
Example: $10,000 long from 65,000 to 68,000 at 0.055% taker. Entry: $5.50. Exit: $10,000 × (68/65) × 0.055% = $5.75. Total: $11.25, or 0.113% of entry notional — your *effective round-trip rate*.
Formula 3: breakeven price
The exit price where gross profit exactly covers both fees. For a long:
Breakeven ≈ entry × (1 + entry rate) ÷ (1 − exit rate)
At 0.055% both ways from 65,000, that's ≈ 65,071.6 — the market must move 0.11% in your favor before you've earned a cent. At Hyperliquid's 0.035% taker the hurdle drops to 0.07%; as a 0.02% maker, 0.04%; on a zero-fee venue like Lighter, breakeven is the entry price itself (plus spread). This single number is the honest price tag of your venue and order-type choices.
Formula 4: discounts stack multiplicatively
VIP tiers and referral discounts apply to the rate, one after the other:
Effective rate = base rate × VIP multiplier × (1 − referral discount)
A 0.055% taker at a VIP tier with a 15% cut and a 10% referral discount pays 0.055% × 0.85 × 0.90 ≈ 0.042%. Small individually; across thousands of trades, structural.
What the formulas don't capture
Fees are the visible cost. Two invisible ones ride along: spread/slippage (you cross the spread as a taker — on thin books this dwarfs the fee) and funding on perps held across intervals, which for multi-day holds usually exceeds trading fees entirely — model it with the funding calculator.
Skip the arithmetic
Our fee calculator runs all four formulas at once: enter exchange, order type, size, leverage and prices, and it returns entry/exit fees, effective rate, breakeven price, and net PnL — then re-prices the identical trade across ten venues so you can see what your current exchange choice costs you. Rates in the calculator are estimates; verify the live schedule on your exchange before trading size.