-840 Odds Explained
- Decimal
- 1.12
- American
- -840
- Fractional
- 5/42
- Implied probability
- 89.36%
- Polymarket
- 89¢
- $100 wins
- 11.90
- American
- -840
- Fractional
- 5/42
- Implied probability
- 89.36%
- Polymarket
- 89¢
- Profit
- 11.90
- Total return
- 111.90
1.119 decimal, -840 American, 89.36% implied probability
-840 is an American price:
the minus sign marks a favourite, and the number is the stake needed to win 100
. Every other format describes the same chance: 1.12 decimal, 5/42 fractional, 89.36% implied probability, 89¢ on Polymarket.
What -840 pays
A 100 stake at -840 returns 111.90 in total: your 100 back plus 11.90 profit. To win exactly 100 you would stake 840.00. The table covers the stakes people actually use.
| Stake | Profit | Total return |
|---|---|---|
| 10 | 1.19 | 11.19 |
| 25 | 2.98 | 27.98 |
| 50 | 5.95 | 55.95 |
| 100 | 11.90 | 111.90 |
| 500 | 59.52 | 559.52 |
| 1,000 | 119.05 | 1,119.05 |
Break-even and long-run results
The implied probability of -840 is 89.36%, and that number is also the break-even win rate: win more often than 89.36% 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% | -44.0% |
| 55% | -38.5% |
| 60% | -32.9% |
| 65% | -27.3% |
| 89% | -0.4% |
A price of -840 is deep odds-on. Bookmakers quote it when an outcome is close to a formality, and the margin they take is proportionally large at this end of the market. Sharp bettors tend to look at the other side of such a market, or at the exchange, where the same favourite is often available a tick or two better.
The vig at -840
If both sides of a two-way market were priced at -840, the implied probabilities would add up to 78.72% above 100%. That excess is the overround, or vig; as a share of stakes it is a 44.05% 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.
-840 on a betting exchange
Exchanges charge commission on net winnings, so the price you see is not the price you get. At 2% commission -840 is worth 1.117 decimal (-857 American); at 5% it drops to 1.113 (-884). Those are the bookmaker prices you would need to beat.
| Commission | Effective decimal | Effective American | Break-even |
|---|---|---|---|
| 2% | 1.117 | -857 | 89.55% |
| 5% | 1.113 | -884 | 89.84% |
Same price in other formats
Nearby prices
Nearby prices
Frequently asked questions
What does -840 mean in betting?
-840 is an American price. Positive numbers show the profit on a 100 stake; negative numbers show the stake needed to win 100. At -840 the implied probability is 89.36% and a 100 stake returns 111.90.
What is -840 in decimal odds?
-840 converts to 1.119 in decimal odds (usually shown as 1.12). Decimal odds are the total return per unit staked, so multiply your stake by 1.119 to get the return.
What is -840 as a fraction?
-840 is 5/42 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 -840?
A 100 stake at -840 wins 11.90 in profit and returns 111.90 including the stake. To win exactly 100 you would stake 840.00.
What win rate do I need at -840?
The break-even win rate equals the implied probability, 89.36%. Winning more often than that at this price is profitable over the long run; winning less often loses money.