Advantage Play & Game Integrity
Arbitrage bets
Arbitrage bets are bets placed on every possible outcome of an event with different bookmakers, sized so the return is the same whichever outcome wins, aiming for a profit when implied probabilities sum below 1.
- Also called
- sure bets, sports arbitrage, betting arbitrage, arb, scalp
- Condition
- The sum of the implied probabilities of all outcomes must be less than 1 (i.e., the sum of the reciprocals of the decimal odds < 1).1
- Applies to
- Fixed-odds markets such as sports betting and horse racing, where different bookmakers offer different lines.3
- Key distinction
- Arbitrage exploits mispriced odds; hedging merely reduces risk.6
Key points
- Arbitrage bets exploit price discrepancies between bookmakers to create a position that yields profit regardless of the event outcome.1
- The bettor places offsetting bets on all mutually exclusive outcomes, calculating stake sizes so each returns the same amount.2
- This strategy is distinct from hedging, which reduces risk without aiming for profit, and from dutching, which equalises returns without requiring a profit condition.4
- Arbitrage opportunities are short-lived and typically require fast action, often using automated tools or bots.3
- The strategy is mainly applied in sports betting and horse racing, where fixed odds from different bookmakers create the necessary discrepancies.5
How arbitrage bets work
- Find two or more bookmakers offering odds on the same event where the implied probabilities of all outcomes sum to less than 1.1
- Calculate the stake for each outcome so the payout is identical whichever wins: stake = (total stake × decimal odds of that outcome) / sum of all decimal odds.
- Place the bets simultaneously. Because the combined implied probability is below 1, the total payout exceeds the total stake, creating a profit opportunity.2
Example
In a tennis match, Bookmaker A offers Player X at decimal odds of 2.10 (implied probability 47.6%), and Bookmaker B offers Player Y at 2.10 (47.6%). The sum is 95.2% — below 100%. Betting £100 on each player costs £200; whichever wins returns £210, for a £10 profit.1
Common questions
How to find arbitrage bets?
Arbitrage bets are found by comparing odds across multiple bookmakers for the same event. Dedicated arbitrage scanning websites and software monitor live odds and alert users when the combined implied probability drops below 1. Opportunities are rare and often vanish within seconds.3
Where this term is used
Related terms
Sources
- Arbitrage betting en.wikipedia.org Provides the definition, condition (sum of reciprocals < 1), and example of arbitrage betting.
- Gambling - Wikipedia en.wikipedia.org Explains how offsetting bets are placed and stakes calculated.
- Advantage gambling - Wikipedia en.wikipedia.org Covers the application to sports betting and the fleeting nature of opportunities.
- Dutching - Wikipedia en.wikipedia.org Distinguishes arbitrage from dutching, clarifying the overlap and difference.
- Fixed-odds betting en.wikipedia.org Confirms that fixed-odds markets are the primary domain for arbitrage bets.
- Betting strategy - Wikipedia en.wikipedia.org Clarifies the difference between arbitrage and hedging.
Sources are drawn from regulators, universities and published research, and each one is labelled with what it actually is — a preprint is not called a paper. Bookmaker and affiliate pages are never cited here, because a page that sells betting is not a neutral authority on it.