How to use the poker variance calculator
- Win rate (bb/100): your true or estimated win rate in big blinds per 100 hands.
- Standard deviation (bb/100): how much your results swing. Typical values are 60–90 for full-ring and 6-max no-limit hold'em, and 100–150 for heads-up or pot-limit Omaha.
- Number of hands: the sample you want to look at. Live players can multiply hours by about 30.
- Big blind ($): optional, to see results in dollars.
What is variance in poker?
Variance is the gap between how you should do based on your skill and how you actually do because of the cards. Even a strong winning player can lose for tens of thousands of hands. Understanding variance helps you avoid tilting during downswings and stops you overrating a lucky upswing.
Standard deviation and confidence intervals
Over N hands, your expected result is win rate × N / 100 and the standard deviation of your result is SD × √(N / 100). About 68% of the time your result falls within one standard deviation of expectation, and about 95% of the time within two.
Poker variance examples
A 5 bb/100 winner over 10,000 hands
With SD of 80 bb/100, expected winnings are 500 bb, but the 95% range runs from about −1,068 bb to +2,068 bb. There's roughly a 27% chance of being a loser over that sample despite being a solid winner.
The same player over 100,000 hands
Expected winnings are 5,000 bb with a 95% range of about 41 bb to 9,959 bb. The chance of being down after 100,000 hands drops to about 2.4%. Larger samples make skill visible.
Expected results and 95% ranges for a winning cash game player at 5 bb/100 with a standard deviation of 90 bb/100:
| Hands played | Expected winnings | 95% range | Chance of being behind |
|---|---|---|---|
| 10,000 | +500 bb | −1,264 to +2,264 bb | 28.9% |
| 50,000 | +2,500 bb | −1,444 to +6,444 bb | 10.7% |
| 100,000 | +5,000 bb | −578 to +10,578 bb | 3.9% |
| 500,000 | +25,000 bb | +12,527 to +37,473 bb | Under 0.1% |
How to handle variance
- Keep a proper bankroll — use the bankroll calculator and risk of ruin calculator.
- Judge decisions, not results. Use EV to evaluate plays.
- Track a large sample before drawing conclusions about your win rate.
Variance calculator FAQ
What standard deviation should I use?
If you track online, use the value your tracker reports. Otherwise 75–85 bb/100 is a reasonable default for 6-max no-limit hold'em and about 65 for full ring.
Does variance apply to tournaments?
Yes, and it's much larger. Tournament results depend on rare deep runs, so you need far more buy-ins and samples.
Why do the graphs look so different each time?
Each line is a random simulation of the same player. That spread is exactly what variance looks like.