Fractional odds
Traditional in Britain. 5/2 means you win £5 for every £2 staked, plus your stake back. A £2 bet at 5/2 returns £7. Evens (1/1) doubles your stake.
Decimal odds
Common online. The number is the total return per £1, stake included. 5/2 is 3.5 in decimal: a £2 bet returns £7. To convert, divide the fraction and add one.
Implied chance
Divide 1 by the decimal odds. 3.5 implies a 28.6% chance; evens (2.0) implies 50%. That is the price talking, not a forecast.
Converter
Type fractional odds such as 11/4 or decimal odds such as 3.75. The implied chance is the bookmaker's price turned into a percentage, before any margin is removed.
The margin inside every market
Add up the implied chances of every outcome in a market and the total comes to more than 100%. In a two-way market priced 1.91 and 1.91, each side implies 52.4%, a total of 104.7%. The extra 4.7% is the bookmaker's margin, and it is why betting costs money over time.
What this guide will not do
We explain how prices work. We do not tip, predict results or suggest any system can beat the margin. None can.