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Arbitrage calculator
An arb is when the best prices for every outcome, usually at different bookmakers, add up to less than 100%. Back every outcome with the right stakes and you profit whatever happens. This arbitrage calculator checks the prices and splits your stake.
Two and three outcome markets
Enter the best price for each possible outcome. Use two rows for a tennis match or another two way market, and three for home, draw and away. The book total tells you whether there's an arb.
Round the stakes if you want them to look like normal bets. The profit then varies slightly by outcome, and the calculator shows each one.
How to spot an arb
Turn each price into an implied chance by dividing 1 by the decimal odds, then add them up. A normal market comes to more than 100%. That extra is the bookmaker's margin. Under 100% is an arb.
| Best prices | Book total | Result |
|---|---|---|
| 1.91 and 1.91 | 104.7% | £4.50 loss |
| 2.00 and 2.00 | 100.0% | £0.00 profit |
| 2.05 and 2.00 | 98.8% | £1.23 profit |
| 2.10 and 2.05 | 96.4% | £3.73 profit |
| 2.20 and 2.05 | 94.2% | £6.12 profit |
Why arbs are rare and risky
- Prices move fast. By the time you place the second bet, the price may have gone.
- Bookmakers can void bets at obvious mistake prices, known as palpable errors. If one side is voided you're left with a normal bet.
- Bookmakers restrict accounts that bet arbs.
- Rules differ. A tennis retirement or a dead heat can settle differently at each bookmaker.
Profit on an arb is usually a few percent of the stake. One mistake can wipe out the profit from many arbs.
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Read the guide: Arbitrage betting explainedRead →Questions people ask
Is arbitrage betting legal?
Yes, it's legal in the UK. Bookmakers don't like it, and they can restrict your account or limit your stakes.
What is a good arb percentage?
Most real arbs are worth a few percent of the total stake. Anything much higher is often a mistake price that a bookmaker may void.
Can I arb between a bookmaker and an exchange?
Yes. Back at the bookmaker and lay at the exchange when the back price is higher than the lay price, after commission. The matched betting calculator handles that.