Loading calculator...
Enter odds from different bookmakers to check for sure bets. The calculator finds optimal stakes for each outcome and shows your locked-in profit.
Moneyline, over/under, or any two-outcome market
Arbitrage occurs when the combined implied probabilities of all outcomes are below 100%. This means the bookmakers disagree on the odds enough that you can bet on every outcome and still profit.
Example: Bookmaker A offers Team X at 2.10, and Bookmaker B offers Team Y at 2.10. The implied probabilities are 47.6% + 47.6% = 95.2%. Since this is below 100%, it is a sure bet with a 4.8% margin.
The key is using the best available odds for each outcome across different bookmakers. Our live arbitrage scanner does this automatically across dozens of bookmakers.
Arbitrage betting (or sure betting) is placing bets on all possible outcomes of an event using different bookmakers, where the combined odds lock in a profit regardless of the result — provided both bookmakers accept and honor the bets. It exploits pricing differences between bookmakers.
The calculator adds up the implied probabilities (1/odds) for each outcome. If the total is below 100%, an arbitrage opportunity exists. It then calculates the optimal stake for each outcome so that every outcome yields the same payout, locking in a profit when both bookmakers honor the bets.
Enter odds in decimal format (e.g. 2.10, 1.85). Decimal odds are the standard in most of Europe and the easiest format for arbitrage calculation. If your bookmaker shows fractional or American odds, convert them to decimal first.
Typical arbitrage margins are 1-5%, meaning a $100 total stake yields $1-$5 in locked-in profit when both bookmakers honor the bets. While margins are small per bet, the math-locked nature makes it attractive for bettors with larger bankrolls. Real-world risks — bookmaker stake limits, voided bets, palp errors, and odds movement before the second leg lands — can reduce or eliminate the edge, so margins are not truly risk-free.
Bookmakers constantly adjust their odds based on betting volume and market movements. When an arbitrage opportunity appears, sharp bettors and automated systems exploit it quickly, causing the odds to shift and the opportunity to close — often within minutes.