The value of a starting hand can change dramatically after the flop. Regardless of initial strength, any hand can flop the nuts—for example, if the flop comes with three 2s, any hand holding the fourth 2 has the nuts. Conversely, the flop can undermine the perceived strength of any hand—A♣ A♥ would not be happy to see 8♠ 9♠ 10♠ on the flop because of the straight and flush possibilities.

There are

(50/3) = 19,600

possible flops for any given starting hand. By the turn the total number of combinations has increased to

(50/4) = 230,300

and on the river there are

(50/5) = 2,118,760

possible boards to go with the hand.

The following are some general probabilities about what can occur on the board. These assume a “random” starting hand for the player.

Board consisting of	Making on flop		Making by turn		Making by river
	Prob.	Odds	Prob.	Odds	Prob.	Odds
Three or more of same suit	0.05177	18.3 : 1	0.13522	6.40 : 1	0.23589	3.24 : 1
Four or more of same suit			0.01056	93.7 : 1	0.03394	28.5 : 1
Rainbow flop (all different suits)	0.39765	1.51 : 1	0.10550	8.48 : 1
Three cards of consecutive rank (but not four consecutive)	0.03475	27.8 : 1	0.11820	7.46 : 1	0.25068	2.99 : 1
Four cards to a straight (but not five)			0.03877	24.8 : 1	0.18991	4.27 : 1
Three or more cards of consecutive rank and same suit	0.00217	459 : 1	0.00869	114 : 1	0.02172	45.0 : 1
Three of a kind (but not a full house or four of a kind)	0.00235	424 : 1	0.00935	106 : 1	0.02128	46 : 1
A pair (but not two pair or three or four of a kind)	0.16941	4.90 : 1	0.30417	2.29 : 1	0.42450	1.36 : 1
Two pair (but not a full house)			0.01037	95.4 : 1	0.04716	20.2 : 1

An interesting fact to note from the table above is that more than 60% of the flops will have at least two of the same suit—you’re likely to either be drawing to a flush or worried about one.

This guide is licensed under the GNU Free Documentation License. It uses material from the Wikipedia.