Arbitrage Calculator

How to use this tool

Enter the requested figures, press the calculate button and review the result. The explanation below shows what each output means.

Enter the best available prices for every outcome in a market, potentially from different sportsbooks, to check whether an arbitrage opportunity exists and calculate the exact stake split needed for an equal, guaranteed return. The sections below explain how arbitrage works and its real practical limitations.

What arbitrage betting actually is

Arbitrage betting exploits situations where different sportsbooks offer sufficiently different prices on the same event that betting all possible outcomes across those different books, in carefully calculated proportions, guarantees a profit regardless of which outcome actually occurs.

This differs fundamentally from ordinary value betting, which accepts genuine risk in exchange for a positive expected value; a true arbitrage, correctly executed, removes risk from the outcome entirely, with the only remaining risk being execution-related rather than tied to the actual result.

How to identify an arbitrage opportunity

An arbitrage exists when the sum of the best available implied probabilities across all outcomes, taken from potentially different sportsbooks for each specific outcome, falls below 100%, the opposite of the overround situation covered in the overround calculator on this site where the sum exceeds 100%.

Finding these situations requires actively comparing prices across many sportsbooks simultaneously, since a true arbitrage typically requires combining the single best price for each individual outcome, prices that are very unlikely to all originate from the same single sportsbook.

Calculating the correct stake split

Once an arbitrage opportunity is identified, the stake for each outcome must be calculated precisely so that the payout is equal regardless of which outcome occurs, a calculation this calculator performs automatically based on the specific prices entered for each side of the market.

Getting this stake split exactly right is essential; an incorrect split can turn a genuine arbitrage into a position that is only profitable for some outcomes and not others, defeating the entire purpose of the arbitrage approach.

A worked two-way arbitrage example

Suppose Sportsbook A offers 2.10 on one side of a two-way market, and Sportsbook B offers 2.05 on the other side. The combined implied probability from these two specific prices falls below 100%, indicating a genuine arbitrage opportunity exists between these two books for this particular market.

Entering both prices and your total intended stake into the calculator above shows the exact amount to place on each side across the two books, along with the guaranteed profit percentage this specific combination of prices produces.

Execution risk in practice

Real-world arbitrage execution carries meaningful risks the pure mathematics does not capture: prices can move between calculating the opportunity and actually placing both bets, one sportsbook might limit or reject a bet before it is confirmed, and account restrictions can develop over time for customers who bet in patterns consistent with arbitrage activity.

These execution risks mean a mathematically perfect arbitrage on paper does not always translate into a guaranteed real-world profit, particularly for bettors operating with limited account history or attempting larger stake sizes that are more likely to attract sportsbook scrutiny.

Why genuine arbitrage opportunities are rare and small

Because sportsbooks actively monitor for pricing discrepancies and other bettors are also searching for the same opportunities, genuine arbitrage windows tend to be small in size, brief in duration, and require considerable effort and speed to identify and execute before they disappear or narrow.

This scarcity is a direct consequence of market efficiency, covered in the price discovery guide within this site's Trading Academy; the more efficiently a market operates, the less room genuine arbitrage has to persist before it is corrected.

Sportsbook account limits and arbitrage

Sportsbooks that identify a customer consistently betting in patterns characteristic of arbitrage, placing offsetting bets shortly after each other across markets, often respond by reducing that customer's betting limits or restricting their account entirely, a specific commercial risk covered in more detail in the market making and liquidity guide within this site's Trading Academy.

This means a sustainable, long-term arbitrage approach requires managing multiple accounts across several sportsbooks carefully, and accepting that individual account limits will likely shrink over time as this activity is identified.

Middling as a related but distinct strategy

A related concept called middling involves betting both sides of a market at different point spread or total numbers, aiming to win both bets if the final result lands between the two numbers, rather than guaranteeing an equal profit regardless of outcome the way pure arbitrage does.

Middling carries genuine risk, unlike true arbitrage, since the final result might not land in the favourable middle range, but it can offer a larger potential payout in exchange for accepting that risk, a different risk-reward trade-off worth understanding as distinct from true, risk-free arbitrage.

Common mistakes with arbitrage betting

A frequent error is calculating an arbitrage opportunity but taking too long to execute both bets, allowing one or both prices to move before the second bet is placed, turning what looked like a guaranteed profit into an unbalanced, genuinely risky position.

A second common mistake is ignoring the specific settlement rules of each sportsbook involved, since minor differences in how a market is defined or settled between two books can occasionally undermine an apparent arbitrage that looked mathematically sound on paper.

Using this calculator responsibly

Treat the output as a starting calculation to verify quickly before execution, not a substitute for genuinely fast, careful execution across the actual sportsbooks involved, and always double-check that both prices remain available and unchanged immediately before placing each half of the arbitrage.

Given the execution risks and account management considerations covered throughout this guide, arbitrage is generally best approached as one specific, narrow tool within a broader betting toolkit rather than a primary, sole strategy.

Time-sensitivity of arbitrage windows

Because arbitrage opportunities can disappear within minutes or even seconds as sportsbooks adjust prices, having accounts already funded and ready across the relevant sportsbooks before searching for an opportunity is a practical necessity for anyone attempting to execute on a regular basis.

Tax and accounting considerations

Depending on your specific jurisdiction, profits from betting activity including arbitrage may carry different tax treatment than other forms of income, an important practical consideration worth researching separately from the pure mathematics this calculator addresses.

A worked two-way arbitrage example

The table below walks through the example described above using a $1,000 total intended stake.

The exact stake split depends on the specific prices involved; the calculator above computes this precisely for your own entered figures, along with the resulting guaranteed profit percentage.

Key takeaways

• A genuine arbitrage guarantees a profit regardless of outcome by combining the best price for each side across books.
• An arbitrage exists when combined implied probability across the best available prices falls below 100%.
• Real-world execution risk, including price movement and account limits, means paper arbitrage isn't always realised.
• Genuine opportunities tend to be small and short-lived given active competition for the same discrepancies.
• Middling is a related but distinct strategy that carries genuine risk, unlike true, risk-free arbitrage.