Arbitrage Calculator
Enter the odds for each outcome and your total stake. The calculator instantly tells you whether an arbitrage (sure bet) exists, the profit % you lock in if every leg is placed at those odds, and exactly how much to stake on each side so your return is the same whoever wins.
How to use it
- Pick 2 outcomes (e.g. tennis) or 3 outcomes (e.g. football 1-X-2).
- Enter the best available decimal odds for each outcome, ideally from different bookmakers or a betting exchange.
- If a leg is on an exchange, enter its commission % (otherwise leave it at 0).
- Set your total stake. The calculator shows the stake per outcome and whether it's a sure bet.
How the maths works
An arbitrage exists when the sum of 1 / odds across all outcomes is less than 1. The profit percentage, if every leg is placed at those odds, is (1 / sum) − 1, and each stake is (1/odds) / sum × total so the return is identical whichever outcome wins. For the full breakdown with a worked example, see how to calculate a sure bet.
What the commission field does
Betting exchanges charge a commission on net winnings, which lowers a leg's effective odds. Enter that percentage and the calculator adjusts automatically — an arbitrage that looks positive before commission can turn marginal after. See how betting exchanges work.
Note
Stakes are rounded to two decimals, so real returns can differ by a cent or two. Odds also move within seconds — by the time you place both legs by hand, the margin may be gone. That's the problem ArbPlay solves automatically.
Frequently asked questions
Is this arbitrage calculator free?
Yes, the ArbPlay arbitrage calculator is completely free and runs in your browser. Enter the odds for each outcome and your total stake to instantly see the stake split, profit percentage and locked-in return if every leg is placed.
What odds format does the calculator use?
Decimal odds (e.g. 2.04). Decimal odds of 2.00 mean an implied probability of 50% (1 divided by the odds). If your bookmaker shows fractional or American odds, convert them to decimal first.
How do I account for betting exchange commission?
Enter the exchange's commission percentage (usually 2%–5%) in the commission field for that outcome. The calculator reduces that leg's effective odds accordingly, so the profit percentage reflects your real net result.
Related: What is arbitrage betting · How to calculate a sure bet · all guides.