Odds guide
How to read American odds
What the plus and minus actually mean, and how to move between American, decimal, and fractional notation.
1. Read the sign
A negative price is the stake needed to win 100 units. A positive price is the profit on a 100-unit stake. The sign tells you which side of even money the outcome sits on, nothing more.
2. Convert to decimal
For a negative price, decimal odds are 1 + (100 / absolute value). For a positive price, decimal odds are 1 + (price / 100). Decimal is the working format because probability follows directly from it.
3. Convert to probability
Implied probability is 1 divided by the decimal price. A decimal price of 2.50 implies 40%. This is still the price before margin, not the market's probability estimate.
4. Check the pair
Convert both sides of a two-way market and add the probabilities. The total will exceed 100%; the excess is the margin you are paying to transact.
Sources
- Source: SportsWager editorial desk
Last reviewed: 2026-08-01