Arbitrage calculator

Enter the best price on each side of a market from different sportsbooks. If the prices add up to less than 100%, the calculator splits your stake so you are paid whichever side wins.

Odds format
Outcomes

Best price on one side, from book A

Best price on the other side, from book B

Spread across every leg

Round each stake to
Edge
+1.92%Implied total 98.11%. Under 100% means the legs pay whichever side wins.
Profit after rounding
+$18.50Lowest return with stakes rounded to $1: +$18.50 if leg 1 wins, +$19.90 if leg 2 wins. Exact stakes would lock +$19.22.
Total staked
$1,000The rounded stakes add up to exactly what you entered.

Stake per leg

  1. Leg 1 at +110

    Stake
    $485
    Exact $485.34, 47.6% of the implied total
    Returns if it wins
    $1,018.50
    Profit if it wins
    +$18.50

  2. Leg 2 at -102

    Stake
    $515
    Exact $514.66, 50.5% of the implied total
    Returns if it wins
    $1,019.90
    Profit if it wins
    +$19.90

How the math works

Every price carries an implied probability: one divided by the decimal odds. A book's own two sides always add up to more than 100%, because the extra is its margin. When two different books disagree enough, the best price on each side can add up to less than 100%. That gap is the edge.

To lock it in, stake each leg in proportion to its implied probability. Every leg then returns the same amount, so the result does not depend on who wins.

A worked example

A total of 44.5 is +110 on the over at one book and -102 on the under at another. In decimal that is 2.10 and 1.98, implied 47.62% and 50.50%, together 98.11%. With $1,000 to spend, the over gets about $485 and the under about $515. Either one returns about $1,019, a profit near $19 whichever way the total lands.

What goes wrong in practice

The line moves. By the time you open the second betslip the price may be gone. Place the leg most likely to move first, and check both prices again before you stake.

The books settle it differently. One book grades an NHL moneyline including overtime, another on regulation time only. If the two legs do not settle on the same rule, it is not an arb. Our settlement rules table shows how each book grades each market.

Exact stakes get noticed. A bet of $485.37 tells a sportsbook a calculator chose it. Rounding to whole dollars, or to $5 or $10 steps, looks like anyone else, and the calculator shows what that rounding costs in profit before you bet.