So, if you’re betting on a horse to win, in a 13 to 2 bet that horse would lose 13 times out of 15. From there you need to look at the two individual numbers to work out the probability of different events taking place. This will give you the total number of instances the outcome has been calculated. The way to work it out is to add both numbers together. The reason for this is that it’s not made common knowledge.ġ3 to 2 is expressing a statistical probability to users through the numbers it shows. On top of that, understanding how probability works is also something that escapes them. Many people don’t understand that all odds, fractional, decimal or American, are essentially a way of expressing a probability. In order to fully understand both we need to go over them separately. In terms of probability and in terms of payout. There are two main factors that go into understanding what 13 to 2 actually means. These are more common at UK sports betting sites, but for certain sports such as horse racing, US betting sites will offer fractional odds. It’s for this reason that it’s normally referred to as fractional odds. 13 to 2 odds will most likely be expressed on betting sites as 13/2.