Understanding odds is the foundation of profitable betting. Here's how each format works.
Decimal Odds (Most Common Online)
The number shows your total return per $1 bet. - 2.00 = $2 return ($1 profit) = 50% implied probability - 1.50 = $1.50 return ($0.50 profit) = 66.7% implied probability - 3.00 = $3 return ($2 profit) = 33.3% implied probability
Formula: Profit = Stake x (Odds - 1)
Fractional Odds (UK Style)
Shows profit relative to stake. - 1/1 (evens) = same as 2.00 decimal - 1/2 = same as 1.50 decimal - 2/1 = same as 3.00 decimal - 5/1 = same as 6.00 decimal
Formula: Decimal = (Numerator / Denominator) + 1
American Odds (US Style)
Positive numbers show profit on $100 bet. Negative show how much to bet for $100 profit. - +100 = same as 2.00 decimal (bet $100, win $100) - -200 = same as 1.50 decimal (bet $200, win $100) - +200 = same as 3.00 decimal (bet $100, win $200)
Converting to Probability
This is the most important skill: - Decimal 2.00 → 1/2.00 = 50% - Decimal 1.50 → 1/1.50 = 66.7% - Decimal 4.00 → 1/4.00 = 25%
Finding Value
If you think a team has a 60% chance of winning but the odds are 2.00 (implying 50%), that's VALUE. The bookmaker is underestimating the probability.
Always calculate implied probability before placing a bet. If your estimate is higher than the implied probability, bet. If not, skip.