Free Poker Tools

Poker Odds and Probabilities

Odds and probabilities are important to the game of poker, they require a little bit of math, but they are really not that difficult once you practice with them. The key is to spend some time working with them so you get comfortable in using them, and understand what is going on.

Why are Odds and Probabilities Important

Why must we understand odds and probabilities? As I explained in another article, the skill part of poker, to a large extent, consists of making good bets and avoiding bad bets. The player who makes the best decisions will win in the long term. Make the wrong decisions, and you will lose over the long term.

In a coin flipping example, there is an equal chance of getting a head or a tail. If you were to put up a dollar for every head that turned up, and your friend put up a dollar for every tail that turned up, you would have an even bet. Since the chances of a head or tail on any coin flip are equal, your odds are also 1 to 1. One time you will win, and one time you will lose. In this example, both you and your friend expect to win the same amount over time, $0. This is neither a good bet nor a bad bet, but neutral. You shouldn't be interested in taking the bet however because the best you can do over time is break even.

On the other hand, if you put up $1 for every head, and your friend put up $2 for every tail, you would have an edge. The chances of flipping heads and tails will still be even, but you get paid more when you win, so over time you will make a profit. This is a bet you should take since you expect to make a profit over time. If you had to put up $2, and your friend put up only $1, you would expect to lose money. This would be a bad bet for you.

In a coin flipping example, the choices are easy to understand, since there are only 2 possibilities. This is not always the case. In poker the choices are much more complicated, which is why it is important to understand odds and probabilities, in order to make good decisions.

Probability

Probability is the likelihood that something will happen. For instance, when you hear the weather report in the morning, and the weatherperson tells you that there is a 20% chance of rain they are saying that the probability of rain is 20%.

Some important concepts to understand here are that if there is a 20% probability that it will rain, there is an 80% probability that it will not rain. Probabilities can not add up to more than 100%, and the sum of all of the various possibilities must add up to 100%.

In simple cases like a coin flip, or the chance of rain, where there are only 2 possibilities, the 2 probabilities will add to 100%. In some situations however there will be more than 2 possibilities. If we only calculate some of the probabilities, they will not add up to 100%, because we did not consider all of the possibilities, but those possibilities still exist, and must add up to 100% in total.

Another way to write the same information is to say that there is a .2 probability of rain, and that there is therefore a .8 probability that it will not rain. The total probability can not be more than 1, and once again all of the possibilities must add up to 1.

Poker Odds and Probabilities - 2