Educational guide
Understanding betting odds
A plain-language guide to decimal, fractional and American odds, implied probability and bookmaker margin.
Written by the WhichBet editorial team · Reviewed 2 August 2026
Three common formats
Decimal odds show the total return per unit staked, fractional odds show potential profit relative to stake, and American odds use positive or negative figures around a 100-unit reference point.
Implied probability
Decimal implied probability is calculated as 1 divided by the decimal price. The combined implied probabilities across all outcomes usually exceed 100%; that excess reflects the bookmaker margin.
Practical checks
- Compare the same market and settlement rules.
- Confirm whether prices include overtime or extra time.
- Never interpret a short price as certainty.
Important: This guide is educational, not financial advice or a recommendation to gamble. Gambling can result in losing the full stake.