In the game of poker, pot odds refer to the ratio of the size of the pot to the cost of the call. In order to determine whether you have a chance of winning any money, it is important to know how to calculate the pot odds quickly. Since pot odds are a ratio, it is easier to convert them to a percentage. Using the example of a $50 pot, with the cost of the call being $10, the ratio is 50:10 or 5:1. If you convert this to a percentage, the pot odds are 20%.

In calculating pot odds, you want to determine if the odds of winning the pot are greater than or lesser than your odds of getting the cards you want for a winning hand. When the pot odds are favorable, then you can go ahead and make the bet. When they are against you, you will be better off if you fold. In online poker it is relatively simple to find the pot odds because the size of the pot is always displayed. Then all you have to do is divide the size of the bet you have to make into this number to find the percentage.

When playing at a table, you do have to be able to do mathematics in your head rather quickly. You have to think about how many outs you have. This is the number of cards remaining in the deck that could give you a winning hand. Since each player at the table gets two cards to start, you can calculate this and add the number of cards the dealer. Since the dealer throws away the first card remaining on the deck, or "burns" it in poker jargon, you can subtract another card. Subtract the total number from 52, since there are 52 cards in the deck.

Divide the number of cards remaining in the deck by the number of outs you have and subtract one. The easiest way to explain how calculating pot odds works is to give an example. Let's suppose that there are five players seated at the table. When you turn over your two cards, you find that you have a queen of hearts and a ten of spades. You need three other cards in sequence to have a straight. So ten cards have already been dealt and the dealer will throw away the next card, leaving 41 cards remaining in the deck. The possible cards that will give you a straight are:

- 8, 9, J
- 9, J, K
- J, K, A
There are twenty possible cards remaining that could make you a winner. These are your outs. Divide 41 by 20, which is 2.5. There must be at least 2.5 bets in the pot in order for you to call.

Some players use the rule of 4 to calculate the odds. At the flop they multiply the number of outs they have by four. If the card doesn't come up, multiply the number of outs by 2 after the turn.