Arbitrage Calculator: Find Guaranteed Profit Bets

Identify guaranteed-profit arbitrage opportunities by comparing odds from different sportsbooks. Enter odds for all outcomes of an event and the calculator will show whether an arb exists, exactly how to split your stake, and your guaranteed profit.

How to Use the Arbitrage Calculator

Select 2-Way for moneyline/head-to-head markets (e.g., tennis, basketball, baseball) or 3-Way for markets with a draw option (e.g., football/soccer, hockey regulation time).

Enter the best available decimal odds for each outcome from different sportsbooks. Optionally enter team/player names and sportsbook names for clarity. The calculator will show:

• Arb percentage — the guaranteed profit margin (positive = arb exists)
• Exact stake split — how much to place on each outcome at each book
• Guaranteed profit — the minimum profit regardless of which outcome wins
• ROI — return on your total investment

What is Arbitrage Betting?

Arbitrage (or “arbing”) exploits price differences between sportsbooks. When two or more books disagree enough on the odds for an event, a bettor can place bets on all possible outcomes and guarantee a profit regardless of the result.

This is possible because the combined implied probability across different books drops below 100%. In a normal market at a single bookmaker, the implied probabilities always sum to more than 100% (that is the bookmaker’s margin). But when you cherry-pick the best odds from different books, the combined implied probability can sum to less than 100% — and the difference is your guaranteed profit.

The Math Behind Arbitrage

The fundamental test for arbitrage is:

(1/Odds_A) + (1/Odds_B) < 1

For a 3-way market (with draw), add (1/Odds_Draw) to the left side.

If the sum is less than 1 (or less than 100% when expressed as percentages), an arbitrage exists. The profit margin equals 1 minus the sum, expressed as a percentage.

Stake Calculation

To guarantee equal profit on all outcomes, the stake on each outcome is proportional to the inverse of its odds:

Stake_i = Total_Stake x (1/Odds_i) / Sum_of_all_(1/Odds)

This ensures that no matter which outcome wins, the total payout is the same — and it exceeds your total investment.

Practical Example

Suppose Manchester United vs Liverpool:

• Book A offers Man Utd at 3.50
• Book B offers Draw at 3.80
• Book C offers Liverpool at 2.30

Check: (1/3.50) + (1/3.80) + (1/2.30) = 0.2857 + 0.2632 + 0.4348 = 0.9837

Since 0.9837 < 1, an arbitrage exists. The profit margin is (1 – 0.9837) = 1.63%.

With a $1,000 total stake:

• Stake on Man Utd: $1,000 x 0.2857/0.9837 = $290.44 at Book A
• Stake on Draw: $1,000 x 0.2632/0.9837 = $267.55 at Book B
• Stake on Liverpool: $1,000 x 0.4348/0.9837 = $442.01 at Book C

Payout if Man Utd wins: $290.44 x 3.50 = $1,016.54 (profit: $16.54)
Payout if Draw: $267.55 x 3.80 = $1,016.69 (profit: $16.69)
Payout if Liverpool wins: $442.01 x 2.30 = $1,016.62 (profit: $16.62)

Guaranteed profit of approximately $16.60 regardless of the result.

Where to Find Arbitrage Opportunities

Cross-Book Comparison

The most common source. Sharp books (Pinnacle, SBOBET) vs. recreational books (DraftKings, FanDuel, Bet365) often have significant price differences, especially on less popular markets. Check odds within minutes of opening — arbs close fast as sharp money moves the lines.

Live Betting

Live/in-play markets are less efficient because books have less time to adjust odds. Arb opportunities appear more frequently but close within seconds. This requires specialized tools and fast execution.

New Player Bonuses

Sportsbook sign-up bonuses can create artificial arbs. If Book A gives you a $500 free bet, you can use it as one side of an arb with guaranteed profit minus only the free bet’s opportunity cost.

Risks of Arbitrage Betting

Account Restrictions

The biggest practical risk. Sportsbooks identify and limit arb bettors aggressively. Signs that trigger restrictions: consistently taking the best odds, never using promotions normally, even staking patterns, winning too much. Most recreational books will limit or ban consistent arbers within weeks to months.

Odds Changes

If odds change between placing your first and second bet, the arb may disappear. You could end up with only one side covered. Mitigate this by placing the less liquid side first and the sharp book second (sharp books are less likely to reject or change odds).

Maximum Bet Limits

Some books cap the maximum bet on certain markets. If you cannot place the full calculated stake on one side, the arb is partially or fully broken. Always check max bet limits before committing to the other side.

Palpable Errors

Sportsbooks reserve the right to void bets placed on “obviously wrong” odds (palpable errors or “palps”). If one side of your arb is voided, you are left exposed on the other side. Be cautious with odds that seem too good to be true — they may be errors rather than genuine arb opportunities.

Arbitrage vs. Value Betting

Arbitrage guarantees profit on every event but requires accounts at multiple books and risks getting limited. Value betting (finding +EV bets using the Expected Value Calculator) is more sustainable long-term: you only need one or two sharp book accounts, your edge is harder to detect, and accounts last longer. The downside is variance — individual value bets can lose, unlike arbs.

Many professional bettors start with arbitrage to build bankroll, then transition to value betting once their recreational book accounts get limited.

Frequently Asked Questions

Is arbitrage betting legal?

Yes. Arbitrage betting is legal in virtually every jurisdiction. You are simply placing bets at different sportsbooks — there is no law against that. However, sportsbooks’ terms of service may restrict your account if they detect arb patterns. This is a business decision by the book, not a legal issue.

How much money do I need for arbitrage?

Most arb opportunities yield 1-5% profit. To make meaningful money, you need a substantial bankroll spread across multiple sportsbooks. A $10,000 total bankroll generating 2% per arb on $1,000 stakes = $20 per event. If you hit 2-3 arbs per day, that is $40-60/day or roughly $1,200-1,800/month.

What arb percentage is realistic?

Most real arb opportunities fall between 0.5% and 3%. Anything above 5% is rare and may indicate a palpable error (which the book might void). The calculator shows the exact percentage so you can evaluate whether it is worth the effort and risk.

Can I arb with just two sportsbooks?

Yes, 2-way markets (moneyline) require exactly two books. However, having accounts at 5-10+ books dramatically increases the number of arb opportunities you can find, because you are more likely to encounter price discrepancies.

Why does the “No Arbitrage” result show a negative percentage?

The negative percentage represents the bookmaker’s margin (overround). For example, -4.5% means the implied probabilities sum to 104.5%. This is normal — it is how sportsbooks guarantee profit. You need to find odds across different books that overcome this margin.