Given that precise EV calculations require one to operate with rather uncomfortable numbers, approximations are used along with simplified models.

For instance, the rule of 4 and 2 allows you to convert outs into % probability, which could then be used to estimate a profitable bet size with reasonable accuracy.

Are there any other similar rules that I've been missing out on? The intention is to be able to estimate odds and derived ROI more accurately, and one of the areas that imo still requires "proper" maths is doing so relative to opponents' stack sizes.

  • Chris Oak, are there any other thumb rules we can use besides the two you mentioned? Are these thumb rules written in a book? Which book? Your website pokergym is closed down so I'm unable to take the math course. Thanks.
    – Grunge
    Jan 27, 2020 at 11:02

2 Answers 2


There are thumb rules for the preflop equity (against a single random opponent) of pocket pairs and suited-connected combos.

For the equity of a pocket pair, you calculate how many cards away from 2 your cards are (for example, Queens are 10 cards away from 2), multiply by 3 and add 50%.

So QQ's preflop equity is approximately:

(10 * 3) + 50 = 80%

For suited-connected combos (JTs, for example) the same rule applies; You calculate how many cards away from two the highest card is (Jack is 9 cards away from 2) and add 30%.

So JTs preflop equity is approximately:

(9 * 3) + 30 = 57%

PokerGym -- Preflop Hand Equity Values

  • 1
    Equity against what ?
    – Peregrine
    Mar 26, 2013 at 16:42
  • The preflop equity against a single random opponent
    – user819
    Mar 26, 2013 at 20:21

When holding a pocket pair, you will hit a set one time in 8. That's 12%. Rough math at the table means that you can set-mine if you expect to make 10x your preflop call amount when the set comes (which is going to be a factor of bet-size, stack-size, and opponent tendencies).

  • I've heard a similar rule; the rule of 10&20. If the ration of effective stacks to pot is less than 10x, it's usually a fold; it they are greater than 20x it's usually a call, and anywhere in between you should rely entirely on other factors (bet-size, stack-size, and opponent tendencies) Mar 28, 2013 at 4:57

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