Understanding odds is the foundation of profitable betting. This guide breaks down decimal, fractional and American odds formats, explains implied probability, and shows you how to spot value in the market.
Decimal Odds
The most common format in European betting. The number represents the total payout per unit staked. For example, odds of 2.50 mean a £10 bet returns £25 (£15 profit + £10 stake).
Implied Probability
Every set of odds implies a probability. To calculate: divide 1 by the decimal odds. So 2.50 implies a 40% chance (1/2.50 = 0.40). When you believe the true probability is higher than what the odds imply, you have a value bet.
The Overround
Bookmakers build in a margin (overround) to guarantee profit. A fair 1X2 market would sum to 100%. In practice, it sums to 103-106%. Lower overround = better value for the bettor. This is why comparing across bookmakers matters.
Practical Tips
Always compare odds across at least 3 bookmakers. Use the OddsFactory comparison tables to quickly identify the best available prices. Even small differences compound into significant value over hundreds of bets.