Arbitrage Calculator
When two books price opposite sides of the same market out of sync, you can stake both sides for a guaranteed return. This tool tells you exactly how much to put on each.
What this means
An arbitrage exists when the sum of implied probabilities across both sides is less than 100%. To lock the profit, divide your total stake so that each side's (stake × decimal odds) returns the same payout — no matter which side wins, your return is the same.
Real arbs disappear quickly. The two main risks: limits (most retail books cap how much they let you risk), and one side moving or being voided before you can place both legs. Place the worse-priced side first — the better-priced side stays good longer.
If the calculator says the implied total is over 100%, this isn't an arb — you'd lose money no matter what.