Sports Betting Arbitrage: How to Lock in Guaranteed Profit

Arbitrage in sports betting is the closest thing to free money. It happens when two sportsbooks disagree on the odds enough that you can bet both sides and guarantee a profit no matter who wins.

A Simple Example

Say the Lakers are playing the Celtics:

DraftKings has Lakers ML at +150
FanDuel has Celtics ML at -130

The implied probabilities are 40% (Lakers) and 56.5% (Celtics). That adds up to 96.5% — which is less than 100%. The gap is your profit.

By splitting your stake correctly between both sides, you lock in roughly 3.5% ROI regardless of the outcome.

How StackDubs Finds Arbs

We scan odds across 8 major sportsbooks in real time: DraftKings, FanDuel, BetMGM, Caesars, BetRivers, theScore, Fanatics, and Hard Rock.

For every game, we check every combination of moneyline, spread, and total odds across all book pairs. When the combined implied probability drops below 100%, that's an arb.

We also show "near-arbs" situations where the hold is under 2-3%. These often become full arbs as lines move.

The Math

For a two-way arb:

ROI% = (1 / (Implied Prob A + Implied Prob B) - 1) × 100

If the ROI is positive, it's an arbitrage opportunity.

StackDubs calculates optimal stake allocation for each leg so you know exactly how much to place on each side for equal guaranteed profit.

Tips for Arb Betting

Act fast. Arb windows close quickly - sometimes in minutes, other times within seconds. Lines move as books adjust.

Round your stakes. Betting exactly $147.32 looks unnatural opposed to $150. While $147.32 reflects the mathematically optimal allocation, sportsbooks have been known to flag accounts that do so which is what we look to avoid.

Use multiple books. You need accounts at several sportsbooks. The more books you have, the more arbs you'll find.

Start small. Books can limit accounts that consistently arb. Keep bet sizes reasonable and mix in recreational bets.

Getting Started

Visit the Arbitrage page. We show every arb opportunity sorted by ROI, with exact stake calculations based on your bankroll. Set your default stake in the sidebar and we'll calculate the optimal split for each leg.

Zero risk. Guaranteed profit. That's arbitrage.