What is a surebet?
A surebet (also called arbitrage or arb) is a situation where the odds offered by different bookmakers allow you to cover all possible outcomes of a sporting event and guarantee a profit regardless of the result. In practice, you place bets on each possible outcome with different operators, and the sum of your winnings always exceeds the sum of your stakes.
Surebets exist because bookmakers don't all set their odds in the same way. Each operator has its own statistical models, its own information sources, and its own customer base. This results in odds discrepancies that, in certain cases, create an arbitrage opportunity. For example, if Bookmaker A offers odds of 2.15 on Team 1 winning and Bookmaker B offers 2.05 on Team 2 winning (in a sport with no draw), the sum of implied probabilities drops below 100%, creating a surebet.
The surebet is the only type of sports bet that truly eliminates risk. It's not about predicting a result or having an opinion on a match — it's about exploiting a mathematical inefficiency in the market. To understand the odds mechanics that make surebets possible, check out our article on understanding odds.
How to calculate a surebet
To check whether a situation constitutes a surebet, add up the inverses of the best available odds for each outcome. If the sum is less than 1, you have a surebet. For example, in a tennis match: odds of 2.20 for Player A (at Bookmaker 1) and odds of 2.00 for Player B (at Bookmaker 2). The calculation: (1/2.20) + (1/2.00) = 0.4545 + 0.5000 = 0.9545. The result is less than 1, so it's a surebet with a guaranteed profit of approximately 4.76%.
To calculate the optimal stakes, distribute your total stake proportionally to the implied probabilities. With a total stake of €100 on the example above: stake on Player A = 100 × (1/2.20) / 0.9545 = €47.62 and stake on Player B = 100 × (1/2.00) / 0.9545 = €52.38. If A wins, you collect 47.62 × 2.20 = €104.76. If B wins, you collect 52.38 × 2.00 = €104.76. The profit is identical in both cases.
Our surebet calculator performs these calculations automatically. Simply enter the odds from each bookmaker and the tool tells you whether a surebet exists, calculates the profit percentage, and recommends the optimal stakes for each outcome.
Finding surebets
Finding surebets manually is an extremely time-consuming exercise. You need to compare odds from dozens of bookmakers across hundreds of sporting events in real time. Opportunities often appear for just a few minutes before bookmakers adjust their odds. For this reason, most arbitrage bettors use automated detection tools that scan odds continuously.
Surebets are more frequent in less popular sports and markets, where bookmakers have less data and adjust their odds more slowly. Niche competitions (second-division handball, challenger tennis, e-sports) offer more opportunities than major football leagues where odds are ultra-efficient. Live surebets (during the match) are more common but require quick execution and carry additional risks related to odds delays.
To exploit surebets, you'll need active accounts at multiple bookmakers with funds available in each. Check our bookmaker comparison to identify the operators offering the best odds and most suited to arbitrage.
Risks and limitations of surebets
Despite its name of "risk-free bet," surebetting carries significant operational risks. The primary one is account limitation: bookmakers detect bettors who practice systematic arbitrage and progressively limit their maximum stakes or even close their accounts. A bettor who only places surebets will quickly be identified by operator surveillance algorithms.
Odds errors (palpable errors) are another risk. Some bookmakers reserve the right to void bets placed on obviously erroneous odds. If one of your bets is voided but the other isn't, you're left with an uncovered single bet. Time delays also pose problems: between the moment you identify a surebet and the moment you place your bets, the odds can change and the opportunity disappear.
Finally, surebet profitability is generally low (1% to 5% per operation) and requires significant capital to generate meaningful returns. Transfer fees between bookmakers and exchange rates (if you bet with operators in different currencies) eat into margins. Sound bankroll management is essential for practicing arbitrage sustainably in the long run.