Definition
A sure bet (or surebet) is an arbitrage opportunity where the combined odds across different bookmakers allow you to cover every possible outcome and guarantee a profit regardless of the result. The term is synonymous with arbitrage but emphasizes the risk-free, guaranteed nature of the profit.
How It Works
A sure bet exists when the sum of the reciprocals of the best available odds for each outcome is less than 1. You calculate the optimal stake for each outcome using the formula: Stake_i = Total Investment x (1/Odds_i) / Sum(1/Odds_j). Each outcome returns the same total amount, ensuring profit no matter what happens.
Example
Boxing match: Fighter A vs Fighter B
- Bookmaker X: Fighter A at 2.20
- Bookmaker Y: Fighter B at 2.05
Check: 1/2.20 + 1/2.05 = 0.455 + 0.488 = 0.943 < 1 -- sure bet of 6.0%!
For a $1,000 total investment:
- Stake on Fighter A: $1,000 x (1/2.20) / 0.943 = $482
- Stake on Fighter B: $1,000 x (1/2.05) / 0.943 = $518
- Return if A wins: 482 x 2.20 = $1,060
- Return if B wins: 518 x 2.05 = $1,062
- Guaranteed profit: approximately $60
Why It Matters
Sure bets are the holy grail for risk-averse bettors -- guaranteed profit with zero risk. However, they require speed (opportunities last minutes), multiple funded accounts, and careful execution. Bookmakers actively fight surebetting by limiting accounts, delaying settlements, and voiding bets placed on stale odds. The margins are typically small (1-5%), so volume is necessary for meaningful returns.
Use our arbitrage calculator to verify sure bet opportunities and calculate the exact stakes needed for each outcome.