Risk of Ruin Calculator
A risk of ruin calculator estimates the probability of losing your entire bankroll based on your win rate, average odds, and unit size. Understanding risk of ruin is essential for bankroll management — even profitable bettors can go broke if they bet too large relative to their edge and bankroll size.
Formula
Risk of Ruin ≈ ((1 - Edge) / (1 + Edge))^(Bankroll / Unit Size)How to Use This Calculator
- Enter your estimated win rate and average odds
- Enter your bankroll and unit size
- View the probability of going broke before doubling your bankroll
- Adjust unit size until risk of ruin is at an acceptable level
When to Use This
- •Determining if your current unit size is too aggressive
- •Understanding how win rate and bet size interact with bankroll risk
- •Setting a bankroll management strategy that balances growth and safety
Risk of Ruin Calculator
Calculate your probability of losing your entire bankroll.
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For informational and educational purposes only. Not financial or gambling advice. All calculations assume odds remain constant and bets execute as entered. Actual results may vary. Gambling involves risk of loss.
Frequently Asked Questions
What is a safe risk of ruin percentage?
Most professionals target a risk of ruin below 5%. This means there's less than a 5% chance of losing your entire bankroll. Recreational bettors might accept 10-20%, but anything above that suggests your unit size is too large for your edge.
How does unit size affect risk of ruin?
Smaller units dramatically reduce risk of ruin. A 1% unit bettor with a 5% edge has near-zero risk of ruin. The same bettor at 10% units has a significant chance of going broke. The relationship is exponential — small changes in unit size have large effects on ruin probability.
Related Glossary Terms
Risk of Ruin
The probability of losing your entire bankroll, even with a positive edge.
Bankroll Management
The practice of managing your gambling funds to minimize the risk of going broke.
Variance
The measure of how much results deviate from the expected outcome in the short term.
Standard Deviation
A statistical measure of how spread out results are from the average.
Kelly Criterion
A formula for calculating the optimal bet size to maximize long-term bankroll growth.
Unit
A standardized bet size used to track performance, typically 1-2% of your bankroll.