Arbitrage Calculator

Arbitrage betting (also called "arbing" or "surebetting") exploits pricing discrepancies between different bookmakers to guarantee a profit regardless of the outcome of an event. Because different sportsbooks set their own odds independently, they sometimes price the same event differently enough that you can bet on all possible outcomes across multiple books and lock in a positive return.

The term originates from financial markets, where arbitrage describes the simultaneous purchase and sale of an asset across different markets to profit from a price difference. In sports betting, the "asset" is the probability of each outcome, and the "price" is the odds offered. When the combined implied probabilities across all outcomes sum to less than 100%, an arbitrage opportunity exists.

Arbitrage is not gambling in the traditional sense. When executed correctly, the profit is mathematically guaranteed before the event starts. It is a form of risk-free trading, though practical limitations (covered below) mean real-world execution always involves some residual risk.

Arb opportunities arise from differences in how bookmakers model and price events. A bookmaker in the US might price a soccer match differently from one in Europe due to different customer bases, different liability exposure, or different modeling approaches. Sharp books (like Pinnacle) set highly accurate lines while square books cater to recreational bettors and may hold stale or inefficient prices longer.

Common sources of arb opportunities include: opening line discrepancies before the market converges, late-breaking news (injury, weather) that some books have priced in and others haven't, live betting where books update odds at different speeds, and player prop markets where books have higher variance in pricing.

The most reliable way to find arbs is using an odds comparison service that monitors hundreds of books simultaneously and alerts you when the combined overround drops below 100%. Manual scanning is too slow for most markets. By the time you spot the discrepancy, it may have closed.

For a two-outcome market (e.g., tennis match win/loss, spread bet), the arbitrage percentage is calculated as:

For a three-way market (soccer: home / draw / away), extend the formula:

To calculate how much to stake on each outcome so that the same guaranteed profit is returned regardless of which outcome wins, divide the implied probability of each outcome by the total arb percentage, then multiply by your total stake. This equalizes your net return across all outcomes.

The guaranteed profit from an arbitrage bet is determined by the arb margin and your total stake. A 3% arb margin on a $1,000 total stake yields a guaranteed $30 profit, but that $30 must be deposited across multiple books, so your capital is temporarily tied up. The effective ROI depends on how quickly you can identify and execute arbs, how much capital you have spread across books, and how fast the books pay out.

Experienced arbers track their "ROI per day of capital at risk" rather than simple profit margin. A 2% arb that you can execute 5 times per day with fast-settling markets is far more valuable than a 5% arb you find once a week. Velocity of capital deployment is the key lever for scaling arbitrage profits.

Despite being mathematically risk-free in theory, several practical factors introduce real risk into arbing:

Bet limits: Winning arbers get their accounts limited or suspended. Sportsbooks are private businesses and can restrict wager amounts to as low as $1 on certain markets for flagged accounts. Once limited, you can no longer place the required stakes to execute arbs, and you may be stuck with one side of a bet already placed. Managing account longevity through bet sizing, recreation bets, and avoiding obvious patterns is essential.

Odds movement: From the time you place your first bet to the time you place your second bet, odds can move. This is especially true in live betting. A "mid-arb" situation, where the second bet is placed at worse odds than when you calculated the arb, can turn a guaranteed profit into a loss. Using fast execution tools and setting hard minimum margins helps mitigate this.

Account restrictions and gubbing: Bookmakers analyze betting patterns. Accounts that consistently bet on value, never lose, and always place maximum amounts on obscure markets are identified and limited. Soft books (William Hill, Bet365, Ladbrokes) are particularly aggressive about limiting sharp action. Maintaining "normal looking" betting behaviour and using multiple accounts (where legally permitted) is common practice.

Withdrawal delays: Capital tied up waiting for withdrawals reduces your ability to execute new arbs. Books with slow processing or strict identity verification requirements reduce the efficiency of your capital.