Enter decimal odds from different bookmakers across all outcomes of a market. If the combined implied probability is below 100%, you have a risk-free profit opportunity — the calculator shows you exactly how much to stake on each outcome.
Enter decimal odds from different bookmakers. If the sum of implied probabilities is below 100%, a risk-free profit exists.
Arbitrage betting (also called 'arbing' or 'sure betting') occurs when you place bets on all possible outcomes of an event across different bookmakers at odds that guarantee a profit regardless of the result. The profit exists because different bookmakers have slightly different odds, and occasionally the combined implied probabilities add up to less than 100%.
Add the implied probabilities (1 ÷ decimal odds) for each outcome. If the sum is less than 1.0 (100%), a risk-free profit opportunity exists. For example, if Home Win = 2.10, Draw = 3.60, Away Win = 4.20, the implied sum is 0.476 + 0.278 + 0.238 = 0.992 (99.2%) — meaning a 0.8% guaranteed profit.
Arbitrage betting is legal but bookmakers dislike it and may restrict accounts of known arbitrage bettors. It is a legitimate strategy of exploiting price differences between markets, similar to financial arbitrage. Always check the terms and conditions of each bookmaker.
Individual arb margins are typically 0.5–5%, meaning a £100 stake returns £0.50–£5.00 guaranteed profit per opportunity. The strategy requires quickly identifying opportunities, placing bets before odds change, and scaling across many events. Professional arbers target hundreds of small profits rather than large individual gains.
Match result (1X2) and Over/Under markets in football, tennis set-winner markets, and head-to-head sports betting markets are common arb opportunities. Pre-match arbs are most reliable while in-play arbitrage requires very fast execution.