What does this result mean?
A tighter margin requires a disproportionately larger sample because the margin enters the calculation squared. It does not promise proof of skill.
Poker sample size calculator
Updated October 2026 · by Tom Howcroft
Plan hands for a chosen normal-model margin of error. Free, no account. See the formula, assumptions and editable inputs.
90
2
777,896.0
Hands required
7,779.0
Equivalent 100-hand blocks
Example
The example inputs below are hypothetical. Change them to inspect your own study scenario. Choose a margin that would change your interpretation of the win rate, rather than selecting one after seeing the result.
Estimates for study and planning only, not a profit promise. Overshove tracks your real sample so these inputs come from your own data.
How to use the answer responsibly
Treat the calculator as a planning tool, not a verdict on one session. A live poker input is usually an estimate: your win rate is noisy, your standard deviation changes by game type, and your future volume rarely matches the clean number you type into a form. The useful habit is to save the assumptions beside the result so you know what would need to change before the decision changes.
If the result pushes against what you wanted to do, do not smooth the inputs until the answer feels nicer. Make the conservative version first, using a lower win rate, a higher swing rate or fewer weekly hours. Then run the optimistic version. The space between those answers is the real decision area: where a shot needs a stop rule, where a move up needs more buy-ins, or where a good-looking hourly still needs a bigger sample.
Overshove calculators become more useful when the inputs come from your own logged sessions. Rake, tips, travel, hours, stake mix and session length all change the number. A generic benchmark can teach the shape of the problem, but a clean personal log gives the number you should actually act on.
Questions
What formula does this tool use?
Hands = ceiling[100 × (1.95996398454 × SD / margin) squared]. SD is the standard deviation of one 100-hand result block; the margin is in BB/100. This assumes independent blocks, stable variance and a normal approximation.
Is this tool free and does it require an account?
It runs in your browser for free with no account. The result is a study calculation under the stated assumptions, not a recommendation to play or a promise of winnings.