Calculate stakes, profits, and ROI for surebets, middles, and lay bets. Supports Asian Handicap, quarter lines, and exchange commission.
A surebet (or arb) is when you bet on all outcomes of an event across different bookmakers, exploiting odds differences to guarantee a profit regardless of the result. If the combined implied probabilities are below 100%, you have an arb. The calculator shows optimal stake distribution and your guaranteed ROI.
A middle is a special type of arb where overlapping lines mean a specific result can win both bets. For example, Over 2.5 at one bookmaker and Under 3 at another. If exactly 3 goals are scored, both bets win. Middles guarantee a small profit on most outcomes with a bonus payout if the result lands in the gap. The calculator tests every possible outcome and shows your profit window.
A lay bet is placed on a betting exchange (like Betfair or Smarkets) where you bet against an outcome. Combined with a back bet at a bookmaker, you can lock in profit from free bets and promotions. A qualifying bet uses real money to unlock a free bet (small loss expected). A free bet (SNR — stake not returned) is then laid off to extract guaranteed value. The calculator accounts for exchange commission.