Poker Variance Calculator

How the variance calculator works

Your result after a number of hands is modelled as a normal distribution. The expected result is your win rate times hands ÷ 100. The spread grows with the square root of the hands played, so it grows more slowly than your expected winnings. That is why short samples are mostly noise and long samples show your real edge.

Risk of ruin assumes you play the same stake forever and never top up. Moving down when you lose a few buy-ins cuts it a lot. See bankroll management and understanding variance, and log your real sessions in the bankroll tracker.

The calculator is built for cash games, where results are measured in bb/100. Tournament results are far more lopsided (rare big wins, many small losses), so a normal model understates their swings. For tournaments, keep 100+ buy-ins as explained in bankroll management.

Frequently asked questions

What is a normal standard deviation in poker?

For no-limit Hold’em 6-max cash games it is usually 80–120bb/100, for full ring 60–90bb/100 and for Pot-Limit Omaha 140–200bb/100. Tracking software such as Hand2Note, HM3 or PokerTracker reports yours once you have a few thousand hands.

What is a good bb/100 win rate?

At micro stakes, 5bb/100 or more is a strong win rate and 1–4bb/100 is solid. Win rates shrink as stakes rise and the games get tougher. Any positive win rate after rake is a winning player.

How many hands until my win rate is reliable?

Far more than most players think. With a 100bb/100 standard deviation, confirming a 5bb/100 win rate with 95% confidence takes about 150,000 hands. After 10,000 hands your true win rate could be anywhere in a range almost 40bb/100 wide.

What is risk of ruin?

The chance of losing your whole bankroll before your edge takes over, assuming you never move down or top up. It falls quickly as your bankroll grows and as your win rate rises relative to your standard deviation.