Every price on a player prop hides a number that matters more than the odds themselves: how often the bet has to win just to break even. Once you can see that number, it’s easy to compare a price with your own read on a player.
American odds in one minute
- Negative odds, like −150, show how much you risk to win $100. At −150 you risk $150 to win $100.
- Positive odds, like +120, show how much you win on a $100 bet. At +120 you risk $100 to win $120.
From odds to break-even
The break-even rate, often called the implied probability, is the share of bets you’d need to win for the price to come out even over time.
Negative odds: |odds| ÷ (|odds| + 100)
Positive odds: 100 ÷ (odds + 100)
| Odds | Break-even |
|---|---|
| −200 | 66.7% |
| −150 | 60.0% |
| −110 | 52.4% |
| +100 | 50.0% |
| +120 | 45.5% |
| +150 | 40.0% |
Why both sides add up to more than 100%
If the over and the under are both −110, each side’s break-even is 52.4%. Together that’s 104.8%, not 100%. The extra 4.8% is the sportsbook’s margin, sometimes called the vig or juice. When both sides are priced, you can remove it by scaling both percentages so they add to 100%, which here gives 50% each.
Putting it to work
Break-even tells you the bar a bet has to clear. If you believe a player goes over 0.5 hits about 62% of the time and the price is −150, the bar is 60%, so your estimate sits 2 points above it. If the price were −200, the bar would be 66.7% and the same estimate would fall short.
GammaLine shows this for every prop: the estimated chance, the break-even for the current FanDuel price, and the gap between them. See how the numbers are laid out.
Published by GammaLine · Updated September 25, 2026
More guides: What are fair odds? Turning a probability into a price · Why a 60% prop still misses