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Arbitrage Betting Calculator (2-way & 3-way)
Enter the best price on each outcome to see if they lock a profit, how to split your stake, and the ROI. If there is no arb, see how far off the prices are.
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| Outcome | Odds | Implied % | Stake | Returns | Profit if it wins |
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Before you place an arb: books limit stakes (often hard on accounts that arb), can void or re-price bets they call an obvious error, and settle some markets differently (overtime, retirements, “action” rules), which can turn a “sure” profit into a loss. Lines also move between your first and second bet, so check the second price is still there before you place the first. 21+. Not betting advice.
Arbs show up when books move at different speeds. See the week’s biggest NFL line moves before kickoff. Get the free Sunday email →
How to use this calculator
Choose a two-way or three-way market and your odds format, enter the total you want to stake, and type the best price you can get on each outcome (each usually at a different book). The green line shows the locked profit and ROI, and the table shows how much to stake on each outcome. If the prices aren't an arb, the red line shows the combined implied % and the price you'd need on the last outcome. Round stakes to $1 or $5 to see what rounding costs you, then copy the result or save it as an image.
How sports betting arbitrage works
Every price implies a probability: −110 is 52.4%, +105 is 48.8%. On one book the outcomes of a market add up to more than 100%; the extra is the hold, the book’s margin (see the hold calculator). When two books disagree enough, the best price on each side can add up to less than 100%. Stake each side in proportion to its implied probability and every outcome returns the same amount, more than you staked. +105 at one book and +102 at another add up to 98.3%, a 1.75% return.
Arbs are small and short-lived, and the risks are practical, not mathematical: limits, voids, settlement rules and moving lines. A hedge on a bet you already hold uses the same math; the hedge calculator shows the stake that locks a profit on an existing ticket, and the odds converter turns any price into implied probability. Line moves are where price gaps open; see this week’s on the line movement checker.
FAQ
How do you calculate an arbitrage bet?
Convert each outcome's odds to implied probability (1 ÷ decimal odds) and add them up. If the total is under 100%, the prices are an arb. Stake each outcome total stake × (its implied % ÷ the combined %); every outcome then returns total stake ÷ combined %, and the profit is that return minus your total stake.
What is a good arbitrage percentage?
Most real arbs are small, often 1% to 3% of the total stake, because books copy each other's prices quickly. A combined implied probability of 98% means about a 2% return; the bigger the gap, the more likely one price is a mistake the book may void.
Is arbitrage betting risk-free?
No. The math is risk-free only if both bets stand at the prices you took. Stake limits, voided or re-priced bets, different settlement rules between books and the line moving before your second bet can all leave you with one side exposed, and books may limit accounts that arb.