Enter your win rate, standard deviation, and bankroll to see your risk of ruin and how wide your results can swing over a stretch of hands.
Risk of ruin (chance of losing the whole bankroll)
4.4%
Expected result
$500
95% range (low)
−$1,068
95% range (high)
$2,068
Over 10,000hands, results this far below expectation are normal — 19 times in 20 you’ll land inside the range above. Big downswings are variance, not necessarily a leak.
Risk of ruin is the chance that variance sinks your whole bankroll before your edge pays off. It falls fast as your bankroll grows: doubling the roll roughly squares the risk. That’s the mathematical case for bankroll management — a bigger cushion doesn’t just feel safer, it makes going broke exponentially less likely.
The 95% range shows how far a normal run can drift from your expected result. Over tens of thousands of hands, even a strong win rate can spend long stretches underwater. Judge your game over big samples, not one bad week. Not sure how big a bankroll you need? Try the bankroll calculator.
Risk of ruin is the probability that normal downswings will wipe out your entire bankroll before your edge plays out, assuming you keep playing the same stake. A lower number is safer; most players aim for a risk of ruin under a few percent.
A common approximation is RoR = e^(−2 · win rate · bankroll ÷ variance), where win rate and standard deviation are measured per 100 hands and the bankroll is in the same currency. Doubling your bankroll squares (dramatically lowers) the risk; a zero or negative win rate makes ruin certain over time.
For no-limit hold’em cash games, standard deviation is often around 80–100 big blinds per 100 hands. Tournaments and looser games swing more. Use your own tracked results when you have them — this calculator lets you plug in any figure.
Variance. Even a solid win rate produces long stretches below expectation — the calculator’s 95% range shows how wide those swings are. A downswing inside that range is statistically normal, not proof of a leak.
Risk of ruin uses the standard exponential approximation and assumes a constant win rate and normally-distributed results. Real results vary. This is an educational estimate based on standard poker math and simplifying assumptions — not a guarantee of results or financial advice. Poker involves chance and variance. Rebuy Labs is software for organizing and studying poker; it does not accept wagers or handle player funds. If gambling stops being fun, call or text 1-800-GAMBLER.
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