Since Texas hold ‘em is the most popular poker variant online, we’ll use it to illustrate calculating hand odds. Calculating hand odds is the most important concept for the poker player to grasp regardless of where he plays, and it represents your chances of achieving a particular hand.
Let’s say you have a hand with two clubs and there are two clubs on the flop. In this scenario, the hand odds for a flush are approximately 2:1. In other words, every three times you play this hand you should achieve the flush once. Of course, it may not work out that way in the short-term, but we can rely on it long-term, so that’s how we want to bet.
Another way to look at your hand odds is in terms of the percentage. If you have hand odds of 3:1, it means that you have a 25% chance of achieving it. That’s because your desired hand is just one of four possibilities. It’s easy to see in a simple scenario but in scenarios that are more complex, you may need to do that math: 1/(X+1). In this example, X equals 3.
In order to calculate your hand odds on the fly, you need to recognize the number of outs that your hand has. An out is simply a card that is available in the deck that helps you achieve your hand. For instance, if you hold the ace and king of clubs and there are two other clubs on the flop, then there are nine more clubs in the deck (in theory). That means nine outs are available to complete the flush.
We say in theory because it is possible that the other players at the table have some or all of those clubs. However, we can only make decisions based on the information that we have. This is where the element of luck enters the game. But we know if we bid this way long-term, we will come at winners in the end, so we go ahead and assume those nine clubs.
Another point to consider is that not all of those nine clubs help you achieve the best possible hand. Typically, you’ll count only the outs that are part of a nut draw. Another point to consider is how the outs affect your opponents. Let’s say the two clubs showing on the flop are consecutive. Well the next club in that series can make a flush for your opponents so we wouldn’t count it as an out.