-121 Odds Explained
- Decimal
- 1.83
- American
- -121
- Fractional
- 81/98
- Implied probability
- 54.75%
- Polymarket
- 55¢
- $100 wins
- 82.64
- The fraction shown is the closest simple fraction to the odds rounded to 3 decimals, not an exact match.
- American
- -121
- Fractional
- 81/98
- Implied probability
- 54.75%
- Polymarket
- 55¢
- Profit
- 82.64
- Total return
- 182.64
1.826 decimal, -121 American, 54.75% implied probability
The price -121 converts to 1.83 decimal odds and 81/98 fractional odds. Read as a probability it says the bookmaker prices this outcome at 54.75%, 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 55¢.
What -121 pays
A 100 stake at -121 returns 182.64 in total: your 100 back plus 82.64 profit. To win exactly 100 you would stake 121.00. The table covers the stakes people actually use.
| Stake | Profit | Total return |
|---|---|---|
| 10 | 8.26 | 18.26 |
| 25 | 20.66 | 45.66 |
| 50 | 41.32 | 91.32 |
| 100 | 82.64 | 182.64 |
| 500 | 413.22 | 913.22 |
| 1,000 | 826.45 | 1,826.45 |
Break-even and long-run results
The implied probability of -121 is 54.75%, and that number is also the break-even win rate: win more often than 54.75% 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% | -8.7% |
| 55% | 0.5% |
| 60% | 9.6% |
| 65% | 18.7% |
-121 sits close to even money. The bookmaker sees this as roughly a coin flip, with the margin nudging both sides of the market a little under fair. Point spreads and totals live here: the line moves to make each side about a 50% proposition, and the price carries the juice.
The vig at -121
If both sides of a two-way market were priced at -121, the implied probabilities would add up to 9.50% above 100%. That excess is the overround, or vig; as a share of stakes it is a 8.68% 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.
-121 on a betting exchange
Exchanges charge commission on net winnings, so the price you see is not the price you get. At 2% commission -121 is worth 1.810 decimal (-123 American); at 5% it drops to 1.785 (-127). Those are the bookmaker prices you would need to beat.
| Commission | Effective decimal | Effective American | Break-even |
|---|---|---|---|
| 2% | 1.810 | -123 | 55.25% |
| 5% | 1.785 | -127 | 56.02% |
Same price in other formats
Nearby prices
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Frequently asked questions
What does -121 mean in betting?
-121 is an American price. Positive numbers show the profit on a 100 stake; negative numbers show the stake needed to win 100. At -121 the implied probability is 54.75% and a 100 stake returns 182.64.
What is -121 in decimal odds?
-121 converts to 1.826 in decimal odds (usually shown as 1.83). Decimal odds are the total return per unit staked, so multiply your stake by 1.826 to get the return.
What is -121 as a fraction?
-121 is 81/98 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 -121?
A 100 stake at -121 wins 82.64 in profit and returns 182.64 including the stake. To win exactly 100 you would stake 121.00.
What win rate do I need at -121?
The break-even win rate equals the implied probability, 54.75%. Winning more often than that at this price is profitable over the long run; winning less often loses money.