Bankroll & Risk of Ruin Calculator
Enter your bankroll in big blinds, win rate and standard deviation: get the probability of ruin and the bankroll needed for a target risk (1%, 5%, 10%).
Overview & Practical Guide
Free poker risk of ruin calculator: estimate the chance of losing your bankroll from win rate and standard deviation, and see how many buy-ins you need to play safely.
Frequently Asked Questions (FAQ)
What is risk of ruin?
The probability that, at a given win rate and variance, you eventually lose your whole bankroll. The normal approximation is RoR = exp(−2 × win rate × bankroll / σ²), with win rate and σ in big blinds per 100 hands.
Which standard deviation should I use?
For 6-max cash games 70–100 BB/100 is typical, 9-max is a little lower and tournament variance is many times higher. Use numbers from your own hand database rather than generic averages.
How many buy-ins do I need?
The lower the win rate and the higher the variance, the more buy-ins you need. The calculator finds the bankroll for your target risk and converts it into 100 BB buy-ins. Conservative players usually aim for 1–5% risk.
How accurate is the result?
It is an approximation: it ignores moving up in stakes, skill growth and the uncertainty of the win rate itself. If your win rate is uncertain (it almost always is), keep a safety margin.
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