-256 Odds Explained
- Decimal
- 1.39
- American
- -256
- Fractional
- 25/64
- Implied probability
- 71.91%
- Polymarket
- 72¢
- $100 wins
- 39.06
- American
- -256
- Fractional
- 25/64
- Implied probability
- 71.91%
- Polymarket
- 72¢
- Profit
- 39.06
- Total return
- 139.06
1.391 decimal, -256 American, 71.91% implied probability
The price -256 converts to 1.39 decimal odds and 25/64 fractional odds. Read as a probability it says the bookmaker prices this outcome at 71.91%, which is the share of the time you would need to win just to break even. A prediction market would quote the same chance as 72¢.
What -256 pays
A 100 stake at -256 returns 139.06 in total: your 100 back plus 39.06 profit. To win exactly 100 you would stake 256.00. The table covers the stakes people actually use.
| Stake | Profit | Total return |
|---|---|---|
| 10 | 3.91 | 13.91 |
| 25 | 9.77 | 34.77 |
| 50 | 19.53 | 69.53 |
| 100 | 39.06 | 139.06 |
| 500 | 195.31 | 695.31 |
| 1,000 | 390.63 | 1,390.63 |
Break-even and long-run results
The implied probability of -256 is 71.91%, and that number is also the break-even win rate: win more often than 71.91% 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% | -23.5% |
| 60% | -16.6% |
| 65% | -9.6% |
| 72% | 0.1% |
With an implied probability of 71.91%, -256 is a moderate favourite. Prices in this band are where the bookmaker's margin is easiest to see: the opposite side of the market is usually priced a little longer than the fair line, and the two implied probabilities add up to more than 100%.
The vig at -256
If both sides of a two-way market were priced at -256, the implied probabilities would add up to 43.82% above 100%. That excess is the overround, or vig; as a share of stakes it is a 30.47% 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.
-256 on a betting exchange
Exchanges charge commission on net winnings, so the price you see is not the price you get. At 2% commission -256 is worth 1.383 decimal (-261 American); at 5% it drops to 1.371 (-269). Those are the bookmaker prices you would need to beat.
| Commission | Effective decimal | Effective American | Break-even |
|---|---|---|---|
| 2% | 1.383 | -261 | 72.32% |
| 5% | 1.371 | -269 | 72.93% |
Same price in other formats
Nearby prices
Nearby prices
Frequently asked questions
What does -256 mean in betting?
-256 is an American price. Positive numbers show the profit on a 100 stake; negative numbers show the stake needed to win 100. At -256 the implied probability is 71.91% and a 100 stake returns 139.06.
What is -256 in decimal odds?
-256 converts to 1.391 in decimal odds (usually shown as 1.39). Decimal odds are the total return per unit staked, so multiply your stake by 1.391 to get the return.
What is -256 as a fraction?
-256 is 25/64 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 -256?
A 100 stake at -256 wins 39.06 in profit and returns 139.06 including the stake. To win exactly 100 you would stake 256.00.
What win rate do I need at -256?
The break-even win rate equals the implied probability, 71.91%. Winning more often than that at this price is profitable over the long run; winning less often loses money.