flush odds

[Bishop]

someone please tell me the math for calculating the odds of catchign the 4th suited card you need for your flush.

ie. YOu have Ax off and the flop is 3 suited cards with your ace, what are the actual odds of catchign the 4th card to make your nut flush and how do you get that number.

Also what would the odds change if you had Kx and the flop was A23 of suited cards meaning there is a possible str8 flush out there? How does that effect your odds of the 4th flush?

[Sven]

If you have 4 suited cards on flop it should be 4.22:1 for the turn and 4.75:1 for river.

[crockpot]

the river figure should be 4.11:1. it's illogical for it to be less likely to hit your flush on the river card, when the deck contains a higher proportion of the suit than before.

the odds of hitting it on either of the last two cards are about 1.9:1.

[Sven]

hehe your right I was thinking about an open ended straight /images/graemlins/smile.gif It's getting late thanks for catching that...

[Nottom]

The numbers are mentioned in the other posts, but as for how to get them here goes.

As you hopefully know you have 9 outs to hit you flush.

On the turn you have a 9/47 chance of hitting and on the river if you miss the turn you have a 9/46 chance of hitting. To get the chance of making it on the turn of the river you can either multiply those 2 together and then subtract out the chance of hitting on both cards since those would be double counted OR you can figure out your chances of missing (38/47*37/46) and subtract that from 1 for you chance of hitting.

And as for worrying about str8 flushes ... don't.