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Free calculator
Compare returns when two lines leave a possible middle.
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Use two distinct lines, decimal odds, and an equal stake for each side.
This model assumes no pushes and one bet winning outside the middle, with both bets winning inside it. Verify market settlement rules for the specific line.
A middle exists when two bets on the same market can both win: for example, backing over 44.5 at one book and under 46.5 at another. Enter both lines and prices, and the calculator shows the middle window, the stake split, and the outcomes in each scenario.
Two opposing bets whose ranges overlap. If the result lands inside the overlap, both bets win; outside it, one wins and one loses, for a small loss.
An arb covers every outcome with no overlap risk. A middle accepts a small loss when it misses, in exchange for a large win when it lands.
Around key numbers: football margins of 3 and 7, basketball totals near round numbers, and line moves triggered by team news.