Originally Posted by LordRahl86

Your chance of making a flush here is actually 36%. It's outs (which are nine) * 2 * cards to come. Since I assume you're folding if you don't make it on the turn, it would be 18% to make it on the turn. You used the wrong formula, but got the odds right.

There are a few questions, though:

1. Will you fold if you don't make the flush on the turn?
2. Will you have the BEST flush?
3. Will they raise it more if you call?

You have to figure what the pot WILL be, and what you will have to put in to it if 1 is false or 3 is true. Aside from that, about 5% of the time (IIRC), there will be two diamonds, which will make it much more likely that your flush is worthless. Edit: Even if that doesn't happen, you still have to take into consideration the possibility that one of your opponents have a higher flush.

However, ASSUMING that the other guy folds, then yes, you'd be getting 2:13 odds. Or something. I need sleep.

Edit2: Just looked it over again. Changed calls to folds.