Arbitrage Betting Calculator
Enter odds from different sportsbooks for each outcome. If the arb percentage drops below 100%, you have a guaranteed profit — and we show you exactly how much to stake on each leg.
New to this? Start with:No-Vig Calculator, +EV Calculator
Quick start
- Enter odds for outcome A from one sportsbook
- Enter odds for outcome B from a different sportsbook
- Check the arb percentage — below 100% means guaranteed profit
- Enter your total stake to see exact amounts per leg
Try a quick example
Book A: Team A at -110, Book B: Team B at +120 — a 97.83% arb yielding a guaranteed $2.22 profit on $100.
Small Arb
Arbitrage exists but ROI is thin. Watch for rounding and limits.
Guaranteed Profit
ROI
Total Stake
Stake Allocation
In plain English
When two books disagree on a line by enough, you can bet every side and lock in a profit no matter who wins. The arb percentage tells you if the gap exists; a single number below 100% is the green light.
Before hunting for an arb, remove the vig from your odds to see the true fair price on each side.
What Is Sports Betting Arbitrage?
Sports betting arbitrage — also called an arb or a sure bet — means betting every outcome of the same event at different sportsbooks so you lock in a profit no matter who wins. It works because each sportsbook sets its own odds, and when two books disagree enough, the combined implied probability of all outcomes drops below 100%. That gap is your guaranteed margin.
The edge does not come from predicting the game — it comes from price differences between books. Because every outcome is covered, the result of the match is irrelevant: the return is fixed the moment you place all the legs. That makes arbitrage one of the few genuinely risk-free strategies in betting, which is also why sportsbooks limit or close accounts they identify as arbing.
How to Calculate Arbitrage Profit
Convert every price to its implied probability — for decimal odds that is simply 1 ÷ odds. Add the implied probabilities of every outcome to get the arb percentage. If the total is below 100%, an arbitrage exists, and your profit margin is 100% − arb%.
Two-way example. Book A prices Team A at +120 (decimal 2.20) and Book B prices Team B at -110 (decimal 1.909). Implied probabilities: 1 ÷ 2.20 = 45.45% and 1 ÷ 1.909 = 52.38%. Added together that is 97.83% — below 100%, so the arb is live and pays about 2.2%. Staking $100 total, you put roughly $54.50 on Team B and $45.50 on Team A and collect about $102.20 whichever side wins. Want the same math on the prices you are looking at? Our no-vig calculator strips the books’ margin so you can compare fair prices fast.
2-Way vs 3-Way Arbitrage
A 2-way arb covers two outcomes — moneylines in sports with no draw (NFL, NBA, tennis). You only need two books and two prices, which is why most beginners start here.
A 3-way arb covers three outcomes — home win, draw, and away win in soccer and other sports that allow a tie. The math is identical, just with one more leg: add three implied probabilities instead of two. For example, Home at 2.70 (37.04%), Draw at 3.40 (29.41%), and Away at 3.10 (32.26%) sum to 98.71%, a 1.29% locked-in margin across three books. Three-way arbs appear more often because three separate prices give the books more room to disagree, but they also need three bets placed quickly before any line moves. Enter 2 to 10 legs above and the calculator handles either case automatically.