Remember back to the day in Probability and Statistics class when you yelled at your teacher saying, "when will knowing the odds of picking a red ball out of a bucket be useful to my life!!" Looks like today is the day. Those equations you dreaded back then are the same ones we can use today when playing Texas Holdem. You limp in on the button with Jc10c. The flop shows 2 more clubs and a diamond. The small blind puts in a nice size bet and there are 3 callers by the time the action gets back to you. As you sit there weighing you options, you realize that it's just a simple math problem. The problem is you don't know the correct formula … but you soon will.

The following chart provides some basic percentages for making various drawing hands you'll have when playing holdem. Instead of memorizing the numbers, a simple rule of thumb for quickly calculating the percentage is to use 2% for each out on the Turn and 2% for each out on the River. As you will see, this gives a fairly accurate estimation for hands with a relatively low number of outs.

 

Drawing Hand	Outs	After the Flop	After the Turn
Pocket Pair -> Set	2	8%	4%
Overcard -> Pair	3	12%	7%
Inside Straight / 2 Pair -> Full House	4	16%	9%
Pair -> 2 Pair or Set	5	20%	11%
2 Overcards -> Pair	6	24%	13%
Open End Straight	8	31%	17%
Flush	9	35%	20%
Flush + Open End Straight	15	54%	33%

 

If you want to be more detailed than the 2% Method, the formula behind the numbers in the chart is as follows:

After the Flop % = 1 - [ ((47-outs) / 47) x ((46-outs) / 46) ]

This formula will give you the percentage of making your hand, provided you see both the Turn and the River. The first grouping represents the odds of making your hand on the Turn ((47-outs) / 47). After the flop, you only know your 2 cards and the 3 community cards, leaving 47 unknown cards. The second grouping represents the odds of making your hand on the River ((46-outs) / 46).