Rather than considering odds in terms of 3 to 1, you can look at them in terms of percentages. First, determine your outs as we did previously. 9 outs to a flush on the turn, with 47 cards possible. Simply get the percentage of 9 to 47 which equals 19%. So, you have a 19% chance of hitting the flush on the turn.

Phil Gordon claims to have named the "rule of two and four". This is a method for approximating the percentages of hitting your outs on either the river alone or the turn and river combined. With 9 flush outs, you multiply by two to get the river percentage; 18%. To get the odds for the turn and river combined, you multiply the outs by 4; 36%. This is not exact, but is a pretty fast and fairly close approximation of the likelihood of hitting your outs. This method tends to get more inaccurate the more outs you have. If you want your results to be more accurate, adjust the rule of four by subtracting one percent for each out greater than 8. For 15 outs, 15 times 4 = 60. 15 - 8 = 7, so 60 - 7 = 53%.

Please note that the rule of four applies to both the turn and river combined. And as we saw earlier, this does not take into account the possibility that you will have to call another bet on the turn. Where this does apply is where one of you will be all in. This means that there will be no bet on the turn and no bet on the river. Say you are playing a tournament and you raise your A8 from late position to 3 big blinds. Other players fold, but the big blind, who only has 7 big blinds left, just calls you. The flop is as before, K65 and the big blind pushes in his last 4 big blinds. Now the pot is your 3 BBs, the small blind's 1/2 BB that he folded, the big blind's 3 BBs to call plus his 4 BBs shove for a total of 10.5 BBs. You have 9 outs = 35% chance of hitting. You are being asked to call 4 BBs into a 10.5 BB pot, so 10.5 + 4 =14.5. Your call of 4 as a percentage of the total future pot of 14.5 = 28%. Your percentage of hitting is better than the percentage that you have to put into the pot, so call.