Risk of Ruin Calculator
for Serious Traders.
Estimate how likely a losing streak is to damage your account. Enter your win rate, reward-to-risk ratio and risk per trade to see the chance of hitting your drawdown limit, how many straight losses it takes to get there, and how your risk size changes the odds.
Strategy settings
Use real numbers from your backtest or trading journal. Guessed inputs give guessed results.
How risk of ruin is calculated
Check your expectancy
If (Win rate × R) − Loss rate is zero or negative, ruin is almost certain over time, however small your risk per trade.
Convert the ruin level to risk units
Ruin level ÷ Risk per trade = how many risk units you can lose before the limit breaks. A 10% limit at 1% risk is 10 units.
Smaller risk lowers the odds
Cutting risk per trade means more straight losses are needed to reach the same limit, so the chance of ruin falls quickly.
Limitations: this is an approximate model. It assumes every trade is independent, wins pay exactly R and losses cost exactly 1 unit, and that your win rate and R stay constant. In practice slippage, spreads, commissions, streaks in your results and changes in position size all affect the outcome. A win rate taken from a small sample can also be misleading. Treat the result as a guide to understanding risk, not a guaranteed forecast.
Tools help you prepare. A clear process helps you apply them.
If you want help reviewing your trading approach, risk management or execution process, explore the Chart Scalping Consultancy service.
Risk Disclosure: Trading forex, CFDs and other financial instruments involves substantial risk. These resources are intended for educational and planning purposes only. They do not guarantee profitable trades or returns. Always verify calculations and rules with your prop firm.