Courtside Lab · Experiment

Arbitrage Line Mover

Drag two books' prices to watch an arbitrage open and close, with the stake split updating live.

The experimentInteractive · no signup
Book Prices
−200even+200
−200even+200
Inverse-odds sum0.9524

< 1 → arb window open

Arb found ✓+$10.00 guaranteed (+5.00%)
The play

Bet $100.00 on Book A at +110, and $100.00 on Book B at +110 , $200.00 staked in total.

If Book A wins
You collect $210.00 → you're +$10.00
If Book B wins
You collect $210.00 → you're +$10.00

Same payout whichever side wins, that's the arbitrage. You lock in the profit no matter the result.

Equal return, either wayguaranteed +$10.00
YOUR STAKEIF A WINSIF B WINS$210.00$210.00GUARANTEED+$10.00+5.0%
$100.0050.0% of totalStake on A
$100.0050.0% of totalStake on B
+$10.00same whichever winsGuaranteed profit
+5.00%on $200 totalProfit %

An arb pays the same whichever side wins. You split your stake across both books so both outcomes return the same payout, more on the lower-priced side, less on the higher. The optimal split is always proportional to each side's implied probability. Books move lines fast, so a small price change flips a guaranteed profit into a loss, drag the slider to feel how thin and fleeting real arb windows are.

Frequently asked2 questions
What is a sports arbitrage?
Betting all outcomes of an event at prices that guarantee a profit regardless of the result, usually by combining odds from different books.
Why do arbs disappear so fast?
Books move lines quickly. The line-mover shows how a small price change flips a guaranteed profit into a loss, which is why arbs are thin and fleeting.
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