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Arbitrage Betting Calculator
Enter the best odds from each bookmaker and instantly see the exact stake split that locks in a guaranteed profit — for 2-way and 3-way markets.
How arbitrage betting works
Arbitrage betting (also called a surebet or sure bet) takes advantage of the fact that different bookmakers price the same event differently. When the odds are far enough apart, you can back every outcome across different bookmakers and guarantee a profit no matter who wins.
1
Find the best odds
For each outcome, take the highest odds available across all bookmakers.
2
Check the arb index
Add up 1 ÷ odds for every outcome. If the total is below 1.0, an arbitrage exists.
3
Split your stake
The calculator tells you exactly how much to place on each outcome so every result returns the same profit.
Frequently asked questions
Is arbitrage betting legal?
Yes. Arbitrage betting is legal in most countries — you are simply placing ordinary bets at different bookmakers. However, individual bookmakers may limit or close accounts that arb frequently, as it is against their own terms.
What is the arb index (L)?
It is the sum of the implied probabilities: L = 1/odds₁ + 1/odds₂ (+ 1/oddsₓ for 3-way). When L is below 1.0, the combined odds guarantee a profit. The lower the L, the bigger the margin.
Why are my stakes rounded?
Bookmakers can flag suspiciously precise stake amounts. Rounding to whole numbers keeps your bets looking natural. The calculator shows both the exact and rounded amounts so you can see the small difference in profit.
Do I need a lot of money to start?
Margins are usually 1–5%, so larger bankrolls produce larger absolute profits. You can start small to learn the workflow, then scale up.