A common question for poker players is "How confident can I be that my winrate is accurate?". Our poker winrate confidence interval calculator can help you answer that.

Why do I need to calculated a winrate confidence interval?

Because poker winnings are subject to random variance, your true winrate is impossible to nail down precisely. Instead we have to calculate a range of possible true winrates based on an observed sample of hands.

Can you give me a concrete example?

Imagine a scenario where you play 50 000 hands of online poker with a winrate of 5BB/100 hands and a standard deviation of 40BB/100. If you want to know what the possible range of your true winrate is with 95% confidence, you would enter 5 in the Winrate input box, 40 in the Std. Deviation input box and 95 in the confidence level box.

Hovering your mouse over the 50 000 hand mark on the chart will show that you can be 95% confident that your true winrate lies between 8.5BB/100 and 1.5BB/100.

How is the confidence interval calculated?

The ev++ poker winrate confidence calculator uses the formulas laid out by BruceZ in the following post on The 2+2 forums.

What is the difference between bb/100 and PTBB/100 (or simply BB/100)?

The measure bb/100 is a short form for big blinds per 100 hands while the terms PTBB/100 and BB/100 refer to big bets per 100 hands where a big bet is defined as being twice the big blind.

How do I find my standard deviation in Poker Tracker 3?

Please refer to this post on the 2+2 forums: find your Standard Deviation in PokerTracker 3.

How do I find my standard deviation in Hold'em Manager?

On the far left of the Reports tab in Hold'em Manager, click on the + sign. Now add the standard deviation and save.