Poker Stack Exchange is a question and answer site for serious players and enthusiasts of poker. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I'm looking for help to build a statistic in excel or just mathematically. What I want to figure is the chance of another player (villain) increase his stack with X BBs when I estimate his BB/100 to be Y against me, with the standard deviation BB/100 being Z and the maximum number of hands we play being A.

An example: I play HU and a player sits down. He's a fish so I estimate his BB/100 vs me to be -30BB/100. The problem is he will quit whenever he's 100BBs up. I know the standard dev to be 100BB/100 and we play a maximum of 200 hands. What is the chance of him reaching a 100BB increase vs me with these numbers?

I figured this was the community to post this in, please let me know if I rather should post this in a more general methematical community.

share|improve this question
This is a rather unusual calculation, but poker does involve a lot of mathematics. So yes, you posted in the right place :) – Radu Murzea May 27 '14 at 21:31
Good Q. I can't answer it, but I tweeted & Facebooked it ;) – Toby Booth May 27 '14 at 22:08

This is a fairly straightforward statistics question. You should look into the z-score for further details.

If we assume your results against this opponent follows a normal distribution, the Excel formula to answer your question would be:

=1-NORMDIST(X, Y * A / 100, Z * SQRT(A / 100), TRUE)

That's the probability your opponent will be ahead at least X BB's after A hands, asssuming Y and Z are in units of BB/100.

share|improve this answer
Thanks a lot and sorry for my late reply! – attenboro Jun 1 '14 at 20:34

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.