In case you have a
draw it is very important to know how much you should
bet in order to make money in the long run. In this way you know when to
call or not. This principle is known as “pot odds”. These “pot odds” determine whether or not you should continue with playing after the
flop.
After the
flop there are three situations possible:
1. You have nothing
When you have nothing, because the
flop wasn't of any help, you should
check and/or
fold. For example you have


and the
flop is


2. You have a good hand
When you have a good hand you should
bet or
raise in most occasions. For example you have


and the
flop is


3. You have a chance to get a good hand
In case you have a
draw you will have to know what the pot
odds are in order to determine whether you should
call or
fold.
Example:
You have


and the
flop is



. In this case you have a
flush draw. When another hearts appears on the
river or the
turn you will have a
flush (and in this case even the best
flush possible: the
nut-flush). In this case, in order to determine the pot
odds you first have to count the number of cards that will give you a
flush. Of the 52 cards which are in the game there are 13 hearts (1/4th). At least four of them are already in the game, you have two in your hands and there are two on the table. This means that there are nine other cards that could give you the
flush. In poker slang it is then said that you have nine “outs”.
An easy way to calculate the chance that the next card is hearts can be done by multiplying the number of
outs with two and then add one.
In this example you'll get: 9x2+1=19 = 19%.
So the chance that the next card (the
turn) is a hearts will be around 19% or a chance of 1 to 5.
After you've determined your chance on a
draw, you will then have to compare this with the amount you'll have to
bet to see the next card in comparison with the amount in the pot.
For example:
There is $9 in the pot and you'll have to
call $1 in order to see the next card. This means that you actually
bet $1 in order to win a pot of $10 ($9+$1). $1/$10 = 10%.
We've just determined that the chance on getting the
draw is 1/5 or 20%. For making a chance on this you only need to
bet 1/10th of the pot. This means you have good pot
odds (percentage of winning is higher than percentage of what it costs) so you should
call.
Let me explain this in another way: The chance you'll get your hearts and thus your
flush is 19%, or around 1/5th. When you win you get $10. So you have a chance of 1/5th to get $10. This means the expected value when calling is 1/5th of $10 is $2 ($10/5). So it will cost you $1 (when you
call) in order to get an expected value of $2!! That's a good pot odd! So you should do that and call!
Determining your pot
odds and playing according to that is guaranteed profitable in the long run (not in the short run, because only in the long run bad luck is averaged out). Bad players do not determine their pot
odds, whereas good players do!!