-257 Odds Explained
- Decimal
- 1.39
- American
- -257
- Fractional
- 7/18
- Implied probability
- 71.99%
- Polymarket
- 72¢
- $100 wins
- 38.91
- The fraction shown is the closest simple fraction to the odds rounded to 3 decimals, not an exact match.
- American
- -257
- Fractional
- 7/18
- Implied probability
- 71.99%
- Polymarket
- 72¢
- Profit
- 38.91
- Total return
- 138.91
1.389 decimal, -257 American, 71.99% implied probability
American odds of -257 mean
you risk 257 to win 100
. In decimal notation that is 1.39, in fractional notation 7/18, and the implied probability is 71.99%. On a prediction market the same price is a 72¢ share.
What -257 pays
A 100 stake at -257 returns 138.91 in total: your 100 back plus 38.91 profit. To win exactly 100 you would stake 257.00. The table covers the stakes people actually use.
| Stake | Profit | Total return |
|---|---|---|
| 10 | 3.89 | 13.89 |
| 25 | 9.73 | 34.73 |
| 50 | 19.46 | 69.46 |
| 100 | 38.91 | 138.91 |
| 500 | 194.55 | 694.55 |
| 1,000 | 389.11 | 1,389.11 |
Break-even and long-run results
The implied probability of -257 is 71.99%, and that number is also the break-even win rate: win more often than 71.99% 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% | -30.5% |
| 55% | -23.6% |
| 60% | -16.7% |
| 65% | -9.7% |
| 72% | 0.0% |
-257 marks a clear favourite without being a lock: the implied chance is 71.99%, 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 -257
If both sides of a two-way market were priced at -257, the implied probabilities would add up to 43.98% above 100%. That excess is the overround, or vig; as a share of stakes it is a 30.54% 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.
-257 on a betting exchange
Exchanges charge commission on net winnings, so the price you see is not the price you get. At 2% commission -257 is worth 1.381 decimal (-262 American); at 5% it drops to 1.370 (-271). Those are the bookmaker prices you would need to beat.
| Commission | Effective decimal | Effective American | Break-even |
|---|---|---|---|
| 2% | 1.381 | -262 | 72.39% |
| 5% | 1.370 | -271 | 73.01% |
Same price in other formats
Nearby prices
Nearby prices
Frequently asked questions
What does -257 mean in betting?
-257 is an American price. Positive numbers show the profit on a 100 stake; negative numbers show the stake needed to win 100. At -257 the implied probability is 71.99% and a 100 stake returns 138.91.
What is -257 in decimal odds?
-257 converts to 1.389 in decimal odds (usually shown as 1.39). Decimal odds are the total return per unit staked, so multiply your stake by 1.389 to get the return.
What is -257 as a fraction?
-257 is 7/18 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 -257?
A 100 stake at -257 wins 38.91 in profit and returns 138.91 including the stake. To win exactly 100 you would stake 257.00.
What win rate do I need at -257?
The break-even win rate equals the implied probability, 71.99%. Winning more often than that at this price is profitable over the long run; winning less often loses money.