Hey sc2zerker,

Sorry for the late reply!

Calculating the odds of hitting a straight or flush is relatively simple. It just requires some probability calculations and counting.

Say you have 87s. There are now a few ways for you to flop a straight.

1) 4,5,6

2) 5,6,9

3) 6,9,T

4) 9,T,J

The order in which these cards come on the flop is irrelevant. Therefore, for each different board there's 4^3=64 ways to make the straight. Since there are 4 different ways to flop a straight, there are 64*4 = 256 flop combinations on which you flop a straight. There are 19,600 different flop combinations available (calculation in spoiler for reference).

50! / (3! * (50 - 3)!) = 19,600

50 different cards, out of which we need 3.

Therefore, the chance of flopping a straight is 256 / 19,600 = ~1.3%

You can apply the same theory to flopping anything else. You have to figure out how many flop combinations will give you a specific hand, and then divide that by 19,600 to find out the probability of flopping that hand.

Hopefully that makes sense

Kind regards,

Tino