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Enter each outcome's odds and your budget to split a guaranteed-profit sure bet - with stake per leg, payout, profit, and ROI.
Enter the odds for each outcome to find arbitrage opportunities.
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Get StartedEstimated typical sports margin by book - illustrative industry ranges, not Spindex-measured.
An arbitrage calculator (or sure bet calculator) finds guaranteed-profit betting opportunities and works out exactly how to split your stake across them. Arbitrage betting takes advantage of sportsbooks pricing the same market differently: when the prices are far enough apart, you can back every outcome and lock in a profit no matter what happens.
Arbitrage - an "arb" or "sure bet" - means covering all outcomes of a market at different books so the combined odds guarantee a return greater than your total stake. It exists whenever the implied probabilities of every outcome add up to less than 100%. The gap below 100% is your edge, and it's risk-free in the sense that the result of the game doesn't matter - you win either way.
First, convert each outcome's odds to implied probability and add them up. If the total is below 100%, you have an arb. Then split your budget in proportion to each outcome's implied probability, so every outcome pays back the same amount. That equal payout, minus your total budget, is your guaranteed profit; divide it by the budget for your ROI.
For example, with one side at 2.10 and the other at 2.05 and a $100 budget, the implied probabilities sum to about 0.964 (under 100%, so an arb exists). You'd stake roughly $49.40 on the first and $50.60 on the second; either way you get back about $103.73 - a guaranteed $3.73 profit, or 3.73% ROI. The calculator runs all of this instantly and even factors in lossback for crypto books.
Choose American or decimal odds, enter the best price you can find for each outcome, and set your total budget. The calculator shows the optimal stake on each leg, the guaranteed payout, your profit, and ROI. Add a lossback % per leg to account for cashback, and use "More bets" for three-way markets. If the market sum is over 100%, it'll tell you there's no arb at those prices.
Arbitrage is legal, but sportsbooks actively discourage it and may limit accounts that do it often. Most arbers stake modestly, spread action across many books, and mix in normal-looking bets. Treat the guaranteed-profit math as the easy part and account management as the real skill.
Arbitrage (an 'arb' or 'sure bet') is when you back every outcome of a market at different sportsbooks so the combined odds guarantee a profit no matter the result. It exists when the implied probabilities of all outcomes add up to less than 100%.
Convert each outcome's odds to implied probability and add them up. If the total is under 100%, an arb exists. Split your budget across the outcomes in proportion to each implied probability so every outcome returns the same amount - that equal return minus your budget is your guaranteed profit.
Your guaranteed return equals your budget divided by the sum of the implied probabilities; your profit is that return minus the budget, and your ROI is the profit divided by the budget. For odds of 2.10 and 2.05 on a $100 budget, the sum is 0.964, so the return is about $103.73 - a $3.73 (3.73%) profit.
Arbitrage betting is legal, but sportsbooks dislike it - they may limit or restrict accounts that do it heavily. It's not against the law, but it can get you flagged, so many arbers spread bets across many books and stake modestly.
A sure bet is another name for an arbitrage - a set of wagers across all outcomes that locks in a profit regardless of which result hits. 'Surebet' and 'arb' are used interchangeably.
Lossback (or cashback / rakeback) is a percentage some crypto sportsbooks return on losing bets. Enter a lossback % per leg and the calculator shows your Max Lossback - extra value you'd recover - on top of the base arbitrage profit.
18+ only · Gamble responsibly · Tools are for informational purposes only.