Arbitrage Betting: How It Actually Works
Arbitrage betting locks in a profit by taking both sides of a market at different books. Here is the math, the risks most guides skip, and what sportsbooks do about it.
Overview
Arbitrage betting — "arbing" — means placing offsetting wagers on every outcome of a market at different sportsbooks whose combined implied probability is under 100%. When that gap exists, the bettor locks in a small profit regardless of which side wins. It is not a get-rich scheme; most arbs yield 0.5% to 3% on stake, and books aggressively limit accounts they catch doing it.
The Math
For a two-way market, compute each side's implied probability. If Book A has Team X at +120 (45.45%) and Book B has Team Y at +110 (47.62%), the combined market is 93.07% — a 6.93% arb. Stake each side inversely to its odds. For a $1,000 total outlay: about $512 on Team X, $488 on Team Y, locked-in return around $1,074.
The formula for individual stake on outcome i is: stake_i = total × (1/odds_i) / sum(1/odds). This is identical math to de-vigging, just run in the opposite direction.
How To Apply It
- Use an odds-comparison tool to surface two-way or three-way markets where combined implied probability is below 100%.
- Act fast — lines move and arbs usually live for seconds to minutes.
- Round stakes to avoid triggering bet-sizing flags; odd numbers scream arber.
- Confirm both bets are accepted before considering the arb complete.
Common Mistakes and Real Risks
- One leg gets voided. Pushes, postponements, or rule differences between books can leave you one-sided with full risk.
- Line moves during placement. You get one leg and the other leg has already shifted.
- Account limits. Books limit or ban profiled arbers quickly, which kills the strategy for anyone at scale.
- Bonus abuse rules. Using promo funds on arbs violates most sportsbook terms.
- Withdrawal friction. Getting money out of limited accounts can take weeks.
Bottom Line
Arbitrage is real math but not a low-variance business. It works best as a supplement to +EV betting, not as a standalone income plan. Manage your bankroll carefully, understand each sportsbook's rules on voids and pushes, and never risk funds you cannot afford to have stuck in limbo. Help is available through 800GAM and ncpgambling.org/chat.