Arbitrage calculator: two books, one guaranteed number
Best price on side A at one book, best price on side B at another. If the implied probabilities sum below 100%, the difference is yours — this computes the profit and the exact stake split that locks it.
Enter both prices to run the check.
How it works
Sum the implied probabilities (1 ÷ decimal odds) of the two best prices. Under 100% → arbitrage: staking each side proportional to its implied probability makes every outcome pay the same. The profit is 1 ÷ sum − 1. Real-world friction is the catch — limits, voided "palpable error" bets, and lines moving between your two tickets.
Frequently asked questions
How does sports betting arbitrage work?
When two books disagree enough, the best price on each side of the same market can imply probabilities that sum below 100%. Stake both sides in the right ratio and every outcome returns the same amount — more than you staked.
What are the real risks of arbing?
Books limit or close winning accounts, void bets on "palps" (obvious errors), and lines move between your two bets, leaving one leg naked. The math is the easy part.
Standard formulas on numbers you provide — not betting advice. 21+ where applicable. Gambling problem? Call 1‑800‑GAMBLER.