Ok, here is a good example. You have AK hearts on board of QhJh6c.

There is 1K in the pot when it gets to you and the bet is 500 (the opponent has made a pot sized bet). Should you call?

Let's take the simple case where you are last to act (so you don't need to consider the pot getting re-raised and thus potentially putting more money in). Further let's say you're against a super tight player and no one else is in the pot. In fact, you know that he will only bet with the nuts. So you put him on QQ in the hole.

1. Pot odds are 1000/500 = 2:1

2. You need to complete your flush or straight to win the hand. Therefore you have 11 outs (all the hearts except the 6h which will pair the board for his full house AND the 3 non-heart 10s which give you a straight).

3. We'll ignore the small chance of the turn and river cards being the same and potentially making your hand but also giving him a boat. Just keep in mind that the answer we get will slightly over-estimate the true amount you should be willing to call.

4. You have 11 outs twice. Wow, that's not on my list. No problem -- use the rule of 4 metioned by aliengenius to figure out the chance of getting your outs by the river, rule of 2 for hitting on the turn. That means about 44% by the river and 22% by the turn. 44% is 4/9 or in other words, 4 times you make it and 5 you don't or odds of 5:4 against. By the turn, it is 22% or 2/9 or 7:2 against.

5. Mathematically, it is not correct to call this bet with only 1 street to come (because 2:1 pot odds -- amount you get paid off -- is less than the 7:2 (or 3.5:1) odds of hitting your flush or straight). If you're down to your last 500 or willing to go to the river, then you will see 2 streets (5:4 odds against hitting) and then this call is justified.

There is a bit more to consider like do you have a deep stack, do you have fold equity (in this case unlikely since villain has the nuts), where you are in a tournament (level, number of players left, near the bubble, etc), etc.

Think about why it is incorrect mathematically to call with only 1 street/card to come: as mentioned above, you make it 2 times for every 7 you miss. So, if you called the 500 there would be 1500 in the pot.

Calling and missing 7 times means you lose 3500. Calling and hitting twice means that you make 3000. So in the long run, your EV (

expected value) of this play is 3000 gained - 3500 lost or -500. (-)EV play is bad!

:turtle: