Converting odds to prices lets sports bettors read prediction market cents in the same terms as the decimal or American odds they already know.
Decimal Odds
Implied probability equals 1 divided by the decimal odds. Odds of 2.50 imply 40%, which matches a price of about 40¢.
American Odds
For positive odds, probability is 100 ÷ (odds + 100). For negative odds, it is odds ÷ (odds + 100), using the number without its minus sign.
The Margin
Sportsbook odds usually include a margin, so implied probabilities add to more than 100%. Market prices can also sum above $1.00 because of spreads.
Worked Example
A sportsbook lists +150 for an underdog. 100 ÷ 250 = 40%, similar to a 40¢ share. If the prediction market shows 36¢, the two venues disagree by about 4 points, which may reflect margins, timing or liquidity.
Key Takeaways
- Decimal: probability = 1 ÷ odds.
- American: use 100 ÷ (odds + 100) for plus odds.
- Margins and spreads push totals above 100%.
- Our odds converter tool can do the maths for you.