To respond to a request on Twitter by JamesM_39:
What are outs in poker?
The number of cards you need to complete your draw or make a specific hand. For example, if you flop a flush draw you have 9 outs because there are nine cards in your suit that are potentially left in the deck that can make your flush. There may not be 9 outs since one or more players may have received your desired suited cards as their hole cards.
Why is it important to know the number of outs?
It is important to know the outs you have since you want to know the probability of making your hand on the the turn and or the river. And you want to compare that outcome with the pot odds are you are getting.
Here is a quick way to handle your outs and the probabilities:
1. If you are only going to see one more card, take the number of outs and multiply it by 2 to get the percentage. With that flush draw, you have 9 outs times 2 or an 18% probability of making your hand on the turn.
2. If you are going to see both the turn and river cards, take the number of outs and multiply it by 4 to get the percentage. With that flush draw, you have 9 outs times 4 or an 36% probability of making your hand on the turn and/or the river.
Now that you can quickly calculate outs into probabilities, let's look at pot odds.
What are pot odds?
Pot odds are simply the amount of money you are betting compared to the amount of money you can win that is already in the pot.
For example, if you are betting $50 to win a pot that has $100, you are betting $1 to win $2. When you convert that into percentages you divide 1 by 3, which is 33%. The reason you divide by 3 and not 2 is that it is like there are three possible outcomes, where one time you win, and the other two times you lose.
Therefore, if you are on a flush draw on the flop and plan to see the river card, you know you have 9 outs or a 36% probability of making your hand. If you had to bet $50 to win $100 in this situation, you would only be getting pot odds of 33%--which is lower than the odds you need of actually making your hand. Therefore, all things being equal, you should fold if this is the only factor to take into your decision.
Odds into Probabilities
Here is a simple chart of the number of Outs and the Estimated Probabilities if you stay to the river. Again, it is simply the number of outs multiplied by 4.
Therefore, now all you have to do is to know how much you are going to bet and compare it to the amount you can win in the pot, in order to get another percentage for your pot odds.
If your pot odds percentage is greater than the number of outs percentage you should stay in the hand and at least call your opponent's bet. Of course, there may be other information you have, which indicates a fold is in order. For example, another player groans when two cards to a flush flops and you hear him whisper to his neighbor, "I mucked a flush draw."
Don't laugh. That situation recently happened to me, and it let me get away from my hand.
I hope this was easy to understand. I know some players don't like to do the math, but poker math is not that difficult. Good luck!