Calculating flush odds

[Hosayif]

Say you've got a flush draw and are against two opponents. Since together they have four cards, in theory there would be one of each suit, so should this affect the number of outs you can count for yourself. Sorry if this is a retarded post, I was just curious.

[nmt09]

I'm still new to poker but the way I work out odds and how Dan Harrington seems to do it in his books is by calculating the unseen cards left.

Therefore even with 6 players left it doesn't alter the fact that after the flop you have 47 unseen cards left, after the turn 46, and on the river 45.


Flush Draw:

Flop (47) 9 outs (5.2:1)
Turn (46) 9 outs (5.1:1)

So to make the call you would have to be getting better pot odds than those on the particular street you're on.

[benkahuna]

On average, your opponents will have the same proportion of flush cards as the deck, mucked cards, and burn cards. So it's best to treat all unseen cards as the same and consider the total number of unseen cards as the pool from which you're drawing. If you take your opponents cards and assume they have something, then the number of available cards in the pool decreases so the proportion of flush cards for you remaining doesn't change that much. This, assuming you can be certain one of your opponents has some of your suit at all.