What is Arbitrage Betting?
5 min read · Free
The Simple Explanation
Arbitrage betting (also called "arbing" or "sure betting") means placing bets on every possible outcome of a game — across different sportsbooks — so that you profit no matter who wins.
It sounds like magic, but it's just math. It works because different sportsbooks set their own odds independently, and sometimes they disagree enough to create a gap you can profit from.
A Real Example (With Numbers)
Let's say it's Chiefs vs. Bills. Here's what two books are offering:
Notice: DraftKings has Chiefs at +135 and FanDuel has Bills at +130. Both are underdogs at these books!
A +135 implies a 42.5% chance. A +130 implies a 43.5% chance. Together, that's only 86% — meaning the books' combined probability adds up to less than 100%. That gap is your profit.
The Bets
Bet $425 on Chiefs at DraftKings (+135)
Bet $575 on Bills at FanDuel (+130)
Total staked: $1,000
What Happens If Chiefs Win?
You collect: $425 × 2.35 = $998.75 from DraftKings
You lose: $575 at FanDuel
Net profit: $423.75
What Happens If Bills Win?
You collect: $575 × 2.30 = $1,322.50 from FanDuel
You lose: $425 at DraftKings
Net profit: $322.50
Either way, you profit. That's arbitrage.
How Do These Opportunities Arise?
Sportsbooks employ teams of people and algorithms to set odds. They're good at it — but they're not perfectly synchronized. Odds change constantly based on betting volume, news, injuries, and other factors.
When they move independently, gaps open. These gaps are usually small (1-3%) and close quickly as bettors exploit them — always confirm the odds are still live at each book before placing both legs.
Is This Legal?
Yes, completely legal — as long as sports betting itself is legal in your state. You're simply placing bets at multiple sportsbooks, which any bettor can do.
Sportsbooks don't love it (they lose money), and they may eventually limit your account if you only arb. But for the purposes of clearing signup bonuses and taking advantage of promos, it's a normal and accepted practice.
What Are the Risks?
- Odds change before you finish. You need to place both bets quickly. If odds move between bets, the arb might disappear.
- Human error. Entering the wrong amount can turn a profit into a loss. Double-check everything.
- Account limits. If you arb frequently, some books may reduce your max bet size.