Arbitrage Calculator

Arbitrage betting—or "arbing"—is basically risk-free betting. You're taking advantage of different odds across bookmakers to guarantee a profit no matter what happens. If Book A has Team X at +150 and Book B has Team Y at +160, sometimes the math works out so you can bet both and make money either way.

The opportunity exists because bookmakers don't all agree on the probability of outcomes. One might be slow to update their lines, another might have taken a bunch of action on one side and need to balance their book, or they might just have different opinions. When the stars align, there's a window where you can lock in guaranteed profit.

Here's the catch: these opportunities are rare, the profit margins are usually small (1-3%), and bookmakers really don't like arbers. Get caught doing it consistently and you'll find yourself limited to tiny bet sizes or banned entirely. But for the time it works, it's about as close to free money as betting gets.

The math for spotting an arb is straightforward. Take the implied probability for each outcome (which you can get from the implied probability calculator), add them up, and if the total is less than 100%, you've got an arbitrage opportunity.

For example: Team A is +120 at Book 1 (45.45% implied probability) and Team B is +110 at Book 2 (47.62% implied probability). Add them up: 45.45% + 47.62% = 93.07%. That's less than 100%, which means there's about a 7% profit margin if you bet the right amounts on each side.

Finding these opportunities manually is tedious. Most serious arbers use software that scans odds from dozens of bookmakers in real-time, alerting them the second an arb pops up. By the time you spot one manually, it's probably already gone.

In theory, arbing sounds perfect—guaranteed profit with zero risk. In practice, there are a bunch of things that can go wrong:

Getting limited: This is the big one. Once a bookmaker identifies you as an arber, they'll restrict your account to max bets of $10 or $20. Suddenly that 3% edge on big stakes becomes pocket change. Some books will just ban you outright.

Odds changes: You place one side of your arb, then go to place the other side and the odds have moved. Now you're exposed. This happens constantly in fast-moving markets or with smaller bookmakers who adjust lines quickly.

Voided bets: One of your bets gets canceled for some reason—maybe there was a last-minute lineup change or a rule issue. Now you've got a regular bet on the other side with no arb protection.

Withdrawal hassles: Moving money between books takes time and sometimes fees. If your bankroll is tied up in slow withdrawal processes, you might miss other arb opportunities.

Pre-match arbs: The classic version, betting on both outcomes before the event starts. These are easier to execute but also more likely to be caught by the bookmaker since you have time to place both bets carefully.

Live betting arbs: These happen during games when in-play odds shift rapidly. Harder to execute because you need to be fast, but less likely to get you flagged since live betting has more variance and looks more like regular betting behavior.

Promotional arbs: Using free bets, risk-free bets, or odds boosts across different books to create guaranteed profit. This is sometimes called "matched betting" and is more sustainable since you're using promos rather than exploiting odds discrepancies.