Arbitrage Betting: The Complete Guide
What is Arbitrage Betting?
Arbitrage betting (arb betting, or "arbing") is the practice of placing bets on every possible outcome of an event across different sportsbooks so that every result pays out more than you staked. It exploits pricing discrepancies between books — when they disagree on the odds enough that the total implied probability drops below 100%.
Unlike other betting strategies, the maths of an arb doesn't depend on who wins — if every leg is placed at the quoted prices, every result returns the same amount. You're not predicting outcomes — you're exploiting the market structure itself.
How a Two-Way Arb Works
The most common arb is a two-way market: two outcomes, two books. Consider a hypothetical NFL game:
| Book | Outcome | Odds | Implied Probability |
|---|---|---|---|
| DraftKings | Chiefs ML | +200 | 33.3% |
| FanDuel | Eagles ML | -105 | 51.2% |
| Total Implied Probability | 84.5% | ||
The combined implied probability is 84.5% — well below 100%. This is an arb. On a $1,000 bankroll, the arb margin is ~18.3% ($183) if both legs are placed at these prices. The arb calculator works out exactly how much to bet on each side.
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Enter any 2 or 3 legs and get the arb margin + exact stakes.Three-Way Arbitrage (Markets with a Draw)
Soccer matches have three possible outcomes — Home Win, Draw, Away Win. Three-way arbs require a profitable price on all three legs simultaneously, making them rarer and shorter-lived. The math is identical: if the sum of all implied probabilities is below 100%, an arb exists.
Calculating Your Stakes
Optimal stake sizing ensures equal returns across all outcomes. The formula for each leg:
Where the Arb Index is the sum of (1 ÷ Decimal Odds) for all legs. If the index is below 1.0, an arb exists and your profit percentage is:
Staking this way returns the same amount whichever leg wins — as long as every leg is placed at these prices.
Risks and Limitations
On paper an arb pays whatever the result; in practice it carries real risks:
- Line moves: You place Leg 1 but the line moves before you place Leg 2. Your arb disappears or reverses.
- Account restrictions: Sportsbooks limit or ban accounts that consistently arb. Bet sizing and book diversity matter.
- Voided bets: If one leg is voided (e.g., injury before game start), your hedge evaporates.
- Withdrawal limits: Large winnings can trigger manual review and slow withdrawals.
Managing these risks is as important as finding the arb itself. Sharp bettors spread action across many books, stay under the radar, and always have both legs ready to place simultaneously.
Finding Arbs: Manual vs. Automated
Manually scanning 20+ books across dozens of markets in real-time is not realistic. Arbs appear and disappear in minutes — often seconds. By the time you find one manually, it's gone.
Dedicated tools like EVstrike monitor every book simultaneously and alert you the moment an arb opens. The window is short, but with automation you can act before it closes.
EVstrike Pro includes a live arbitrage finder with real-time alerts, covering game markets and player props across 20+ books.