-255 Odds Explained
- Decimal
- 1.39
- American
- -255
- Fractional
- 20/51
- Implied probability
- 71.83%
- Polymarket
- 72¢
- $100 wins
- 39.22
- American
- -255
- Fractional
- 20/51
- Implied probability
- 71.83%
- Polymarket
- 72¢
- Profit
- 39.22
- Total return
- 139.22
1.392 decimal, -255 American, 71.83% implied probability
American odds of -255 mean
you risk 255 to win 100
. In decimal notation that is 1.39, in fractional notation 20/51, and the implied probability is 71.83%. On a prediction market the same price is a 72¢ share.
What -255 pays
A 100 stake at -255 returns 139.22 in total: your 100 back plus 39.22 profit. To win exactly 100 you would stake 255.00. The table covers the stakes people actually use.
| Stake | Profit | Total return |
|---|---|---|
| 10 | 3.92 | 13.92 |
| 25 | 9.80 | 34.80 |
| 50 | 19.61 | 69.61 |
| 100 | 39.22 | 139.22 |
| 500 | 196.08 | 696.08 |
| 1,000 | 392.16 | 1,392.16 |
Break-even and long-run results
The implied probability of -255 is 71.83%, and that number is also the break-even win rate: win more often than 71.83% of the time at this price and you profit in the long run, win less often and you lose. The table shows the return on stake at a few win rates, including the break-even rate itself.
| Win rate | Return on stake |
|---|---|
| 50% | -30.4% |
| 55% | -23.4% |
| 60% | -16.5% |
| 65% | -9.5% |
| 72% | 0.2% |
-255 marks a clear favourite without being a lock: the implied chance is 71.83%, so the bookmaker expects this outcome roughly two times in three. Moneylines on the better team in an evenly scheduled league, the higher-ranked tennis player, or the "under" in a low-total game are typical places to see it.
The vig at -255
If both sides of a two-way market were priced at -255, the implied probabilities would add up to 43.66% above 100%. That excess is the overround, or vig; as a share of stakes it is a 30.39% margin for the bookmaker. Removing it leaves fair odds of 2.00 decimal ( +100) on each side. Use the devig calculator to do the same for any market.
-255 on a betting exchange
Exchanges charge commission on net winnings, so the price you see is not the price you get. At 2% commission -255 is worth 1.384 decimal (-260 American); at 5% it drops to 1.373 (-268). Those are the bookmaker prices you would need to beat.
| Commission | Effective decimal | Effective American | Break-even |
|---|---|---|---|
| 2% | 1.384 | -260 | 72.24% |
| 5% | 1.373 | -268 | 72.86% |
Same price in other formats
Nearby prices
Nearby prices
Frequently asked questions
What does -255 mean in betting?
-255 is an American price. Positive numbers show the profit on a 100 stake; negative numbers show the stake needed to win 100. At -255 the implied probability is 71.83% and a 100 stake returns 139.22.
What is -255 in decimal odds?
-255 converts to 1.392 in decimal odds (usually shown as 1.39). Decimal odds are the total return per unit staked, so multiply your stake by 1.392 to get the return.
What is -255 as a fraction?
-255 is 20/51 in fractional odds, the traditional bookmaker notation where the top number is profit and the bottom number is stake.
How much do I win on a 100 bet at -255?
A 100 stake at -255 wins 39.22 in profit and returns 139.22 including the stake. To win exactly 100 you would stake 255.00.
What win rate do I need at -255?
The break-even win rate equals the implied probability, 71.83%. Winning more often than that at this price is profitable over the long run; winning less often loses money.