Odds can be displayed in 2 different ways: Fractions or Decimals.
Most people will be used to seeing odds as fractions (e.g. 2/1). But they can also be displayed as decimals (e.g. 3.00).
It's important to know whether you're looking at your odds as decimals or fractions, because 2.00 in decimal odds doesn't translate as 2/1 in fractions, just as 10/1 in fractions doesn't convert to 10.00 in decimals and so on.
Decimal odds are fairly simple once you've got the hang of them. Basically, you multiply your stake by the decimal shown and the answer is how much you'll receive in winnings – including your stake.
E.g. If you have odds of 5.00 and stake £1, you'll receive £5 in winnings (including your returned stake).
What are Fraction Odds?
Odds displayed as fractions show how much you will win on a bet compared to how much you put on it. The first number in the fraction shows how much you will win if you place the amount shown in the second number.
E.g. If you have odds of 2/1 and stake £1, you'll receive £2 in winnings (not including your stake).
This works on a ratio basis, so if you place £10 at 2/1, you'll receive £20 winnings (not including your stake)