In the simplest of terms, pot odds in poker represent the ratio between the size of the pot and the bet the player is facing.
For example, if you’re facing a bet of $50 and there is $100 in the pot, you need to call $50 to win $150. Thus, your pot odds are 3 to 1.
On their own, pot odds aren’t too useful. However, when combined with your chances of winning, i.e., your equity in the hand, pot odds can tell you when to call and when to fold; thus, knowing how to calculate this number is one of the fundamental poker skills. Learn more about pot odds.