Playing Texas hold’em, after the flop, if you hold a drawing hand, it is important to understand and know how to use the pot odds and the card odds.
It is not that difficult. Doing so will make it easy to decide whether you should continue to invest in that hand: Do you have a positive expectation?
The pot odds are simply the number of chips in the pot, including the last bet/raise by an opponent, compared to the number of chips you must call to see the next card. For example, let’s say there are 20 chips already in the pot, and you must call a 4-chip bet to stay in the hand, then the pot odds are 20 divided by 4. That is 5-to-1 – very easy to figure.
A bit more complicated is calculating your card odds. What are the odds of catching the card that makes your hand and hopefully big enough to win the pot? To facilitate the calculation, you can use a chart such as the following. Alternatively, you can use the 4-2 Rule which allows you to do the calculation in your head to get a reasonable estimate.
The 4-2 Rule and how it works: Count your outs – the number of cards that will make your hand. After the flop, simply multiply your card outs by 4 for the odds of catching one of your outs on the turn or on the river. Then, if you fail to connect on the turn, multiply your card odds by 2 for the river.
Compare this with the pot odds. If the pot odds are higher than the card odds, you have a Positive Expectation. The laws of probability favor you. In the long run, you will be a winner.
What if the numbers are close, or if the pot odds are slightly lower than the card odds? In that case, use the implied pot odds: Estimate the pot odds after including the number of chips that will likely be added to the pot on subsequent rounds of betting. Use that new total divided by your cost to call the next bet, to determine if the pot odds are still higher than the card odds.
It takes only a second or two to use the 4-2 Rule. It is a reasonable estimate that is suitable for our purposes.
But there are also bad outs. All card outs are not the same. Bad outs are those that might also benefit your opponent. He could make a better hand than you do. They could be very costly when you catch one.
If you believe one of your outs is in that category, it would be best not to include it in your count or reduce its value.
As an example: You are drawing to an open-end straight; that gives you 8 card outs. You believe your opponent is drawing to a heart flush, for which 2 of your 8 outs would make his hand. What if the turn makes your straight, but he makes a flush with the same card? In that case, your good outs are reduced to 6 (rather than 8). If you are not too sure, then you might reduce your outs to 7.