Joined: Feb '08
Location: United Kingdom
Age: 33 (M)
Posts: 1886

I'm not quite sure what you're asking but calculating odds preflop is just the same as calculating odds post flop. You take the number of positive results/cards that you want to see and put it in a fraction over the total number of possibilities. Of course there are more cards so the maths is longer but if you want to be accurate you'll need a poker calculator. You can get these on other sites that I'm not allowed to mention here. To be honest though, I don't think there is as much need for preflop odds calculations as post flop. For example, post flop you can be raised with a flush draw. You then need to guess what cards you can hit to win and calculate the odds of getting them on the turn or river. Pre flop you don't really know what flop you want to get. But if you get QQ for example and someone goes all in you can assume you don't want a K or an ace to come. This is pretty easy to calculate roughly. Assume they have AK there are six cards to avoid, forty eight unknown cards remain, chances of first card being A or K is 6/48 or 1/8. Multiply this by five community cards but bear in mind that each time they miss there is one less card in the deck. The chances of them hitting A or K is approximately 5/8 but your chances of hitting a Q are 2/48 x 5 (approx 1 in 5). therefore chances of you winning are about 50/50