Definition
Arbitrage (also called surebet or arb) is a technique that exploits pricing discrepancies between different bookmakers on the same event. By placing bets covering every possible outcome across different bookmakers, you lock in a guaranteed profit no matter what happens. It is the closest thing to risk-free money in sports betting.
How It Works
An arbitrage opportunity exists when the sum of the implied probabilities of the best available odds for each outcome is less than 100%. You check this with the formula: (1/Odds_A + 1/Odds_B) < 1. The difference from 1 represents your arbitrage margin -- the guaranteed profit percentage.
Example
Tennis: Djokovic vs Alcaraz
- Bookmaker A offers Djokovic at 2.15
- Bookmaker B offers Alcaraz at 2.10
Check: 1/2.15 + 1/2.10 = 0.465 + 0.476 = 0.941 < 1 -- that is a 5.9% arbitrage margin.
For a total budget of $1,000:
- Stake on Djokovic (Bookmaker A): $494.15
- Stake on Alcaraz (Bookmaker B): $505.85
- Guaranteed profit: ~$62 regardless of who wins.
Why It Matters
Arbitrage is one of the few mathematically guaranteed ways to profit from sports betting. However, opportunities are rare, short-lived, and typically yield small margins (1-5%). Bookmakers actively limit or close accounts of known arbers. Success requires accounts at many bookmakers and fast execution -- a single odds change can turn a surebet into a loss.
Always double-check your calculations before placing arbitrage bets. A stale odds quote can turn a guaranteed profit into a guaranteed loss.