Free tools
Arbitrage Calculator
Enter two prices from two books on opposite sides to see whether the split pays no matter who wins.
Free, no account needed. Informational, not betting advice. 21+.
Results
- Arb exists
- Yes
- Arb margin
- +2.44%
- Profit
- +$2.50
- Stake at book 1
- $50.00
- Stake at book 2
- $50.00
- Payout either way
- $102.50
Both prices together add to under 100%. The split below returns the same payout whichever side wins.
Lines move and books limit stakes. Confirm both prices before you place either bet.
How it works
Add the implied probabilities of the two prices. Below 100%, an arb exists and the margin is 100% minus the total. Split the stake in proportion to each side’s implied probability so both payouts are equal. Profit is that payout minus the total stake.
Worked example
+105 at one book and +105 at another imply 48.78% each, 97.56% in total. The margin is 2.44%. $100 splits $50 and $50, both sides return $102.50, and the profit is $2.50 either way.
When to use it
Arbs appear when two books disagree. A check shows the listed books’ prices on each leg; if one book is clearly out of line, this tool sizes the two sides. Lines move fast and books limit accounts that do this often, so confirm both prices before you place either bet.
Questions
Why is the margin not the same as the profit?
Margin is 100% minus the total implied probability. Profit as a share of stake is 100% ÷ total − 100%. At 97.56% they are 2.44% and 2.50%. Both are shown.
What can go wrong?
A line moves after you place the first bet, a book voids one side, or a book limits your stake below the split. Each leaves you with one open bet at its original risk.
Why are the stakes uneven?
Each stake is sized so both sides return the same payout. The side with the shorter price needs more money.
Can a market with a push be an arb?
A push returns the stake on that side only. Spreads and totals on whole numbers can push, so a two-way split may not cover every result. Use half-point lines, or treat three-way markets with care.
Is this betting advice?
No. The tool is arithmetic on the numbers you type. EdgeFast is informational price discovery, not a sportsbook, and you decide whether to bet. 21+ only.
Related tools
Now check a real price.
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Informational, not betting advice. 21+.