Arbitrage Betting Calculator
Identify arbitrage opportunities and calculate the exact stakes to guarantee profit on every outcome.
What Is Arbitrage Betting?
Arbitrage betting (or "arbing") exploits pricing differences between sportsbooks to guarantee a profit regardless of the outcome. When two or more bookmakers disagree on the probabilities of an event, their combined implied probabilities can drop below 100%, creating a window where a bettor can back every possible outcome and still profit.
For example, if Sportsbook A offers the home team at +160 and Sportsbook B offers the away team at +155 in a two-outcome market, the combined implied probability is 38.5% + 39.2% = 77.7%. Because this is well under 100%, there is a 22.3% theoretical arbitrage margin. In practice, margins are much tighter — typically 1-5% — but they represent guaranteed, risk-free profit.
Arbitrage is legal, but sportsbooks discourage it. They may limit or close accounts of frequent arbers. The strategy requires multiple funded sportsbook accounts, fast execution, and accurate calculations — which is exactly what this calculator provides.
How the Arbitrage Calculator Works
Enter the odds from each sportsbook for every outcome in a market. The calculator converts them to implied probabilities and sums them. If the total is below 100%, a guaranteed arbitrage opportunity exists.
The calculator then determines the optimal stake for each outcome based on your total bankroll, ensuring that every possible result returns the same profit. It displays your guaranteed profit amount, ROI percentage, and the exact dollar amounts to place on each side.
The tool supports both 2-way markets (moneylines, spreads, over/unders) and 3-way markets (soccer match results with draw outcomes). It handles American, decimal, and fractional odds.
Finding Arbitrage Opportunities
Arbitrage opportunities arise from several sources: different sportsbooks having different opinions on probabilities, delayed line adjustments after news breaks, promotional odds boosts, and cross-market inefficiencies. The most common scenario is comparing odds across 5-10 sportsbooks for the same event.
Speed is critical. Arb windows typically last minutes to hours before books adjust their lines. Having accounts funded and ready to bet, with the ability to quickly calculate stake sizes, is essential. Even small delays can result in one side of your arb being taken before you can place the second bet.
Typical arb margins range from 1% to 5%. On a $1,000 total stake, a 3% arb yields $30 guaranteed profit. While modest on a per-bet basis, consistent arbing can generate reliable returns with zero risk.
Worked Example: NFL Moneyline Arbitrage
You find the following odds for an NFL game: Sportsbook A has Team X at +165, Sportsbook B has Team Y at -155. Your total bankroll for this arb is $1,000.
- Convert to implied probability: +165 → 37.74%, -155 → 60.78%
- Total implied probability: 37.74% + 60.78% = 98.52%
- Since 98.52% < 100%, an arbitrage exists. Margin: 1.48%
- Stake on Team X (Sportsbook A): $1,000 × (37.74% / 98.52%) = $383.09
- Stake on Team Y (Sportsbook B): $1,000 × (60.78% / 98.52%) = $616.91
- If Team X wins: $383.09 × 2.65 = $1,015.19 payout → $15.19 profit
- If Team Y wins: $616.91 × 1.645 = $1,014.82 payout → $14.82 profit
Regardless of which team wins, you profit approximately $15 on your $1,000 investment — a guaranteed 1.5% return with zero risk. Over 100 such bets, that compounds to $1,500+ in risk-free profit.
Frequently Asked Questions
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