Calculating Poker Odds

The words used to describe different odds and percentages can make the whole area more confusing than it should be. On this page, what I mean by "poker odds" is the is the X:1 ratios in that you would find in a Pot Odds Chart.

First, don't be confused by the way the Odds are written. When you see 4:1, it means for every 4 times one thing happens (usually you miss the draw), 1 different thing happens (you catch your draw). It does not mean something will happen once in four times.

Here are some odds examples . . .

Coin Flips
A coin will land on heads one time for every time it lands on tails (over time). The odds of landing heads on a flip of a coin are 1:1.

You will notice it cannot be read "one time in one try" correctly. If you remember the coin flip example, you can correctly read the odds chart from here on out.

If something happens once in five tries (20% of the time), it is expressed as 4:1.
For every 4 times one thing happens : 1 other thing happens

If something happens once in four tries (25% of the time)
For every 3 times one thing happens : 1 other thing happens
It is expressed as 3:1

Now, with that all behind us, let's look at the math behind the numbers in our Pot Odds Chart.

The formula for computing the Odds of a given poker situation is:

We can take the percentages from the probability chart, or we can compute the poker probabilites ourselves, but we need the probabilities for the formula.

One of the most common situations that Pot Odds are used for is sitting on an open-ended straight, waiting on the river card. Let's compute the Pot Odds in that situation.

Odds = ( 1 / .174 which is the value from the chart for 8 outs on the river ) - 1
Odds = ( 5.747 ) - 1
which gives us 4.75

So, the Pot Odds required to chase an open-ended straight at the river profitably are 4.75:1.

For the incurably curious, that is how you compute the Odds in any given poker situation.

I recommend just printing out a chart of Pot Odds, and using that instead of computing these values. If you use an Odds Chart, after a short time you will find that you have the most commonly used numbers memorized.

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