Free tool
Arbitrage betting calculator
Enter the best price on each side of a market from two different books. The calculator tells you whether an arb exists, how to split your stake, and the profit you lock in regardless of the result.
Arbitrage calculator
best price on side A
best price on side B
split across both sides
Combined implied probability is under 100%
Same payout whichever side wins
Yours regardless of the result
Arbs are thin and short-lived; lines move and books limit accounts. The math only holds if both prices are still live.
How an arb works
When two books disagree enough on a two-way market, you can back both sides at prices whose combined implied probability is under 100%, a guaranteed profit no matter who wins. Enter both prices and your total stake, and the tool splits it so every outcome returns the same amount.
What to watch for
Arbs are real but thin and short-lived: lines move fast, limits are low, and books may void or limit accounts that arb aggressively. Treat the calculator's output as the moment-in-time math: the edge only holds if both prices are still live when you place both legs.
Frequently asked
What is arbitrage betting?
Arbitrage (or an arb / sure bet) is backing every outcome of a market at different books for prices that guarantee a profit regardless of the result. It exists when the books disagree enough that the combined implied probability of all outcomes is below 100%.
Is arbitrage betting legal?
Arbitrage itself is legal: you're just placing bets at advertised prices. However, sportsbooks dislike it and may limit or close accounts that do it repeatedly. The bigger practical risk is execution: a line moves before you complete both legs, leaving you with one-sided exposure.
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