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Risk of Ruin
Monte Carlo simulation of bankroll survival — see the probability of going broke given your edge and bet sizing
Read the guide →Settings
Inputs
Your historical or expected win rate
Typical odds you bet at
Starting bankroll
Flat bet amount per wager
Betting horizon (max 10,000)
Risk Analysis
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About Risk of Ruin
Risk of ruin is the probability that your bankroll drops below the amount needed to place a single bet. Even with a positive edge, aggressive bet sizing or a small bankroll can lead to ruin through natural variance. This calculator uses Monte Carlo simulation to estimate ruin probability over your betting horizon with flat (fixed-dollar) bet sizing.
A common guideline is to keep your bet size under 2-5% of your bankroll (matching the Kelly Criterion output). If your risk of ruin is above 10%, consider reducing your bet size or increasing your bankroll.