Quick answer: Betting odds show two things at once: how much you win, and how likely the bookmaker thinks an outcome is. Decimal odds of 2.00 double your stake and imply a 50% chance. To turn decimal odds into a probability, divide 1 by the odds: 1 ÷ 2.00 = 0.50 = 50%.
What are the three odds formats?
- Decimal (2.00), total return per 1 unit staked.
- Fractional (6/4), profit per stake (win 6 for every 4).
- American (+150 / −200), +150 stakes 100 to win 150; −200 stakes 200 to win 100.
What is the bookmaker margin?
Add up the implied probabilities of every outcome. A fair market totals 100%; bookmakers price it above 100% and that extra is their margin, or overround.
