How the arbitrage calculation works
Add up the implied probability of the best price on each outcome. Below 100% means an arbitrage exists. Each stake is then proportional to that outcome's implied probability, so every outcome pays the same.
stake on outcome = total stake × (1 ÷ odds) ÷ Σ(1 ÷ odds)
Example
One book has +110 and another has -105 on the other side. The implied total is 98.84%, so it's an arbitrage. On $100, bet $48.18 at +110 and $51.82 at -105: either way you're paid $101.18, a profit of $1.18 (1.18%).
FAQ
What is arbitrage betting?
Arbitrage means betting every outcome of an event at different sportsbooks when their prices disagree enough that the combined bets pay out more than the total stake, whichever side wins.
Is arbitrage betting risk-free?
Not in practice. Prices can move before both bets are placed, a book can void a bet it considers mispriced, and books may limit accounts that bet arbitrage. Check each book's terms before betting.
How big are arbitrage margins?
Usually small, often a few percent or less, which is why stakes have to be split precisely. This calculator rounds to the cent; round your actual bets carefully so every outcome still pays.