Arbitrage Betting Calculator
Use this free arbitrage betting calculator to find guaranteed-profit bets and split your stake in seconds. Enter the odds for two opposing outcomes, and the tool tells you whether an arbitrage (or “arb”) exists, how much to bet on each side, and your locked-in profit and ROI. It works with American or decimal odds.
What Is Arbitrage Betting?
Arbitrage betting means backing every outcome of an event at odds that, taken together, guarantee a profit no matter what happens. It works when two sportsbooks disagree enough on a price that the combined implied probability drops below 100 percent. The arbitrage betting calculator above does the math for you and splits the stake so each result pays the same.
How to Use the Arbitrage Calculator
Pick your odds format, enter the price for Outcome A and Outcome B (ideally the best price for each side from different books), and set your total stake. The calculator instantly shows whether an arb exists, the exact amount to bet on each side, the payout, and your guaranteed profit and ROI. If the combined implied probability is under 100 percent, you have an arb.
Worked Example
Say Team A is +120 (decimal 2.20) at one book and the other side, Team B, is +110 (decimal 2.10) at a different book. The implied probabilities are 1 / 2.20 = 45.45 percent and 1 / 2.10 = 47.62 percent, a total of 93.07 percent. Because that is under 100 percent, an arb exists. On a $100 total stake you would bet about $48.84 on Team A and $51.16 on Team B. Either result pays roughly $107.45, a guaranteed profit of about $7.45, or 7.45 percent ROI.
Free Printable Arbitrage Worksheet
Want to plan both legs on paper before the line moves? Download the free printable arbitrage betting worksheet to record each sportsbook, market, odds and stake, then work out your guaranteed profit and ROI by hand.
Download the Arbitrage Worksheet (PDF)
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Arbitrage Calculator FAQ
What is an arbitrage betting calculator? An arbitrage betting calculator checks whether two opposing odds (usually from different sportsbooks) let you bet both sides and lock in a profit no matter the result. It also tells you exactly how much to stake on each side.
How do you know if an arbitrage bet exists? Convert both odds to decimal and add their implied probabilities: (1 / Odds A) + (1 / Odds B). If the total is under 1.00 (100%), an arbitrage opportunity exists and the calculator shows a guaranteed profit.
How is the stake split calculated? Each side is staked in proportion to its implied probability so both outcomes return the same payout. Stake on a side = Total stake times (1 / that side’s odds) divided by the combined implied probability.
Is arbitrage betting legal? Arbitrage betting is legal in most places, but individual sportsbooks may limit or close accounts that do it heavily. Always check the rules where you are and bet responsibly.
Why do arbitrage opportunities disappear so fast? Sportsbooks adjust their lines quickly, so an arb can vanish in minutes. That is why a fast calculator and a printable worksheet to plan both legs before you place them are useful.
