There are three major odds formats, that is ways to display what your odds are. Traditionally in the UK the most common way has always been fractions, this is where the first number spoken is the amount you will win for every second number you stake. The two numbers put together is your total return. For example 8/1 means you will win £8 profit for every £1 you stake, the total return from the bookmaker will be £90 if you win. More common these days is the European system of using Decimals. This would display 8/1 simply as 9. Nine is the total amount you get back and has already included the stake in this calculation, but 8/1 and Decimal 9 are exactly the same thing. It is possible, although very unlikely, that you might want to use US odds. These are quite simple when it is odds against because for example 2/1 is +200, 4/1 is +400, 5/1 is +500, etc etc. It is simple to just think if how many % you multiply your stake by. It gets a lot more confusing when it is odds on, because you may have -400. Now -400 is the inverse of +400, so 4/1 becomes 1/4, which is Decimal 1.25. Our advice is that if you can use Decimal then do that because it is the quickest and simplest one to work out in your head.