You have four hearts and need a fifth. Somebody bets. Is calling a good idea or a bad one? There is a way to know, and it is easier than it sounds.
There are two numbers. How often you will make your hand, and how often you need to. If the first is bigger than the second, call. That is the whole thing, and the rest of this page is just how to get those two numbers without a calculator.
An out is a card still to come that turns your hand into a winner. Counting them is just counting.
| What you have | Outs | Why |
|---|---|---|
| Four to a flush | 9 | Thirteen of each suit, you can see four of them |
| Four to a straight, open at both ends | 8 | Four cards at each end |
| Four to a straight, needing one in the middle | 4 | Only the one rank helps |
| Two overcards | 6 | Three of each rank left |
Nine outs on the flop is about 36% to get there by the end. Nine outs on the turn, with one card left, is about 18%. That is it — no other arithmetic is needed.
Now the other number. Compare what the call costs you with what you would win.
There is 500 in the pot and it costs you 100 to call. If you call, you are risking 100 to win 600 — the 500 that is there plus your own 100. So you need to win about one time in six, which is roughly 17%.
Your flush draw gets there 36% of the time. You only need 17% to break even. So calling is clearly right — and it stays right even though you will miss the flush nearly two times in three.
You will make this call, miss, and lose the pot far more often than you win it. That does not make it a bad call. Over a season of poker nights the money comes back, and then some. Judge the decision, not the result.
Flip the example. If the pot is 200 and someone bets 400 into it, calling costs 400 to win 1,000 — you would need to be right about 40% of the time. A flush draw at 36% is not enough. Fold.
Two more cards are still to come. How many of them help you?