Arbitrage betting calculator

Compare the full market

At 2.10 on each side of a two-outcome market, a $100 total splits into $50 per side. Either winning side returns $105 before costs. This is an arithmetic example using hypothetical prices, not a live opportunity.

Recalculate after rounding stakes

Actual stakes need currency precision. Rounding can make the returns differ, so the result must show each rounded stake and the lowest net result. A small apparent margin can disappear after costs.

Matching settlement is essential

The calculation assumes every possible outcome is covered, all stakes are accepted and the bets settle under identical rules. Limits, price changes, voids and commissions can change the result. The tool does not monitor operators or place bets.

Back/lay, commission and free bets

A lay stake is not its liability. At lay odds of 3.10, a $98.04 lay stake exposes about $205.88 if the backed outcome wins. A $100 cash back bet at 3.00 with 4% lay commission balances to about −$5.88 either way. A stake-not-returned free bet uses only the back profit as its available winning return; its nominal stake is not treated as cash invested. Check offer and exchange terms separately.

Dutching and three-way surebet calculations

For decimal prices D₁ through Dₙ, add 1/Dᵢ to obtain Q. With budget B, the equal-return stake on outcome i is B × (1/Dᵢ) / Q. A theoretical positive arbitrage needs Q < 1 before costs. Dutching can equalize a return even when every outcome loses money.

For a three-way market at 3.20, 3.20 and 3.20, Q is 0.9375. A $96 budget splits into $32 per outcome, each returning $102.40 and giving $6.40 net before costs. Include home, draw and away; omitting a possible result does not cover the market.

Matched betting and lay liability

Back/lay mode distinguishes a cash back stake from a stake-not-returned free bet. Enter both prices and the exchange commission. Lay liability is lay stake × (lay odds − 1), which differs from the lay stake itself.

This is arithmetic for entered prices and settlement rules. Different void rules, limits, commissions or price changes can remove a theoretical margin. A biased allocation or a betting middle is not equal-return dutching; use the middle bet calculator to compare its separate outcomes.

Execution and commission can remove a paper arbitrage

A displayed positive net assumes that every listed price is available for the stated stake and that all bets are accepted under matching rules. A suspended market, changed price, rejected stake or different void treatment can leave an uncovered outcome.

Use the rounded stake outputs, not the unrounded allocation, to assess the smallest outcome return. Back/lay commission applies to exchange winnings under this model; it is not interchangeable with a fee on stake. The hedging calculator compares a second wager with an existing ticket.

A positive book margin may not survive cent rounding

American +110, decimal 2.10 and fractional 11/10 describe the same price. You can enter any of these formats. A $100 budget at 2.10 on both outcomes produces $5 net either way. But a $0.03 budget at the same prices must split into $0.02 and $0.01: the second outcome returns $0.021, below the total stake. The result therefore flags the lowest rounded outcome even though the theoretical book percentage is below 100%. Actual operator minimums and payout rounding may be stricter.