Poker Variance Calculator

How variance works in cash games

Your true win rate is hidden underneath a mountain of variance. Even a strong 5bb/100 winner with a typical 100bb standard deviation will have 30%+ stretches of losing play over 20,000 hands. That isn't a leak. That's math.

The chart you are about to generate is the same idea every grinder eventually internalises. Take your true win rate, take a typical standard deviation for your game, run thousands of imaginary careers in parallel and see where the bands land. The gold zone is two standard deviations wide, which is the window the math says you live in 95% of the time. The rest of the time, you are either bragging or sulking, and probably both.

What the outputs mean

Expected profit is your true mean. Standard deviation of result is roughly your sd × √(hands/100). The 95% CI is mean ± 1.96 × that. Probability of losing money is the area of the normal curve below zero.

For a deeper read on why so many breakeven players think they're losers, see our essay on poker variance.