Arbitrage Calculator
Enter odds from two different sportsbooks for opposing outcomes to see whether an arbitrage exists and how to split your stake.
Stake on A
$49.40
Stake on B
$50.60
Profit on Either Result
$3.73
ROI
3.73%
Bookmaker Margin
-3.60%
What Is Arbitrage Betting?
Arbitrage betting (or "arbing") uses odds differences between sportsbooks so that, once every stake is placed, the return is the same whatever the result. An arb exists when the implied probabilities of all outcomes sum to less than 100%. Odds can move before every bet is placed, and a voided bet or a staking mistake can still lose money.
Formula: If (1/OddsA + 1/OddsB) < 1, an arbitrage opportunity exists. The margin below 100% is your return on the total stake once both bets are placed at those odds.
Frequently Asked Questions
What is arbitrage betting?
Arbitrage means backing every outcome of an event at different books whose combined implied probability is below 100%, so the return is the same whatever the result once every bet is placed at those odds.
How do I know if an arb exists?
Add the implied probabilities (1 divided by decimal odds) of all outcomes. If the total is below 100%, there is an arbitrage, and the lower the total, the bigger the margin.
How do I split my stake across an arb?
Stake each outcome in proportion to its implied probability so every result returns the same amount. This calculator works out each stake and the profit on either result.
Is arbitrage betting legal?
Arbitrage is legal, but books may limit or close accounts they identify as arbing. Margins are small and odds move fast, so execution speed matters.
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