Formula
Cost/trade = notional × [2 × commission% + 2 × slippage% + spread%]
One basis point is 0.01%. The result multiplies cost per round trip by the number of completed trades.
Backtest cost calculator
See what trading costs remove from a backtest.
Estimate commission, slippage, and spread across a fixed number of round-trip trades. The calculator keeps position notional constant so its assumptions remain visible and easy to reproduce.
Estimated result
These values use constant position notional on every trade and subtract estimated costs from the gross result.
- Net profit or loss after costs
- $880.00
- Total estimated costs
- $320.00
- Net return
- 8.8%
- Cost per round trip
- $3.20
- Break-even move per trade
- 0.32%
- Position notional
- $1,000.00
- Gross profit or loss
- $1,200.00
| Cost component | Across all trades |
|---|---|
| Commission | $200.00 |
| Slippage | $100.00 |
| Spread | $20.00 |
Estimated cost drag on starting capital3.2%
How to use the result
- Copy the fee schedule and slippage assumption used in the actual backtest.
- Stress-test at higher costs instead of relying on one optimistic estimate.
- Compare net return, drawdown, profit factor, and trade evidence together.
Known limitations
This simplified model holds position notional constant. It does not model compounding, changing position size, funding, borrow costs, taxes, price impact, partial fills, or tiered fee schedules.
Risk note
This calculator is an educational estimate, not financial advice or a broker fee quote. Historical simulations and cost estimates do not guarantee future fills or performance. Confirm current fees and market conditions with the relevant venue before making any real trading decision.
Commission and fees guide · Slippage guide · Backtest methodology