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Martingale calculator

Doubling up after a loss makes a smooth curve, until the losing run that wipes it out. See when.

How it works

After each loss the next trade's lot is multiplied (rounded to the 0.01 lot step brokers use). The table shows the lot and the total lost after each run of losses, and the exact chance of at least one run that long in your number of trades, if every trade has the same win rate.

Why sellers like it, and why it breaks

Most of the time a win comes soon and the curve looks smooth, which makes a backtest or a signal record look brilliant. But the losses grow faster than the wins, and over enough trades a long losing run is close to certain. That one run can take more than every win before it.

Grids work the same way: more and bigger trades as price moves against you. NoCap Edge looks for both in a backtest or statement. See backtest red flags or check a real file.

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Education, not financial advice. Simple models with the assumptions shown; real trading has costs, gaps and rules these leave out. Nothing you type here leaves your browser.

More: Position size · Drawdown recovery · Losing streaks · Prop challenge odds