Poker Math Made Easy – The Rule of 4 and 2

Some poker players have no trouble at all with the math that is necessarily a part of poker. Others, well, they have to play by “feel”, because the math just escapes them. If you are in the latter group, here is an easy way to approximate your chances of making or improving your hand.

After the flop, count your outs. For example, if you are four to the flush, you have nine outs. If you have an open-ended straight draw, you have eight outs. There may be several ways to improve your hand, so figure out the total number of outs. Now, multiply your outs by four, and that will be your approximate percentage chance of improving/making your hand. If you want to get more specific, subtract one percent for every out you have in excess of eight outs. So, if you have nine outs, the math goes like this: 9 x 4 = 36 – 1 = 35%. That formula works after the flop.

After the turn, the math is different. Multiply your outs by two and then add two to that number. So, if you miss your flush card on the turn, with one card left to come on the river, and still nine outs, your odds of making the flush are about 20% : 9 x 2 = 18 + 2 = 20%.

This trick won’t give you the exact percentage, but it gets you close enough to consider your bet as a percentage of the total size of the pot. If you have a 20% chance to make your hand, and you are required to call a bet less than 20% of the total pot, the math says you should call. If the required bet as a percent of the total pot exceeds your chances of making your hand, the math says you should fold.

Keep in mind that this does not take into consideration implied odds. Pot odds may say fold, whereas implied odds may say call. For instruction in implied odds, read any of the excellent books from Two Plus Two publishing, several of which are available further down this page.