Arbitrage (Surebet)
Identify locked-in profits by exploiting price discrepancies across different sportsbooks.
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Inputs locked
odds
2.15, 1.95
totalStake
1000
Result snapshot
roi
2.26%
profit
22.56
payout
1022.56
impliedSum
97.79%
Next step
18+ where legal. Educational calculator only. Bet sizing outputs are not financial advice.
How Arbitrage Betting Works — The Math Explained
Arbitrage betting (or "arbing") exploits pricing differences between bookmakers. When bookmaker A offers Team X at 2.15 and bookmaker B offers Team Y at 2.05 on the same game, the sum of implied probabilities is 46.5% + 48.8% = 95.3% — below 100%. Bet proportionally on both sides and you lock in a 4.7% guaranteed profit regardless of outcome.
The formula: if implied probability sum < 1.00, you have an arb. The profit percentage = (1 / sum) − 1. For each outcome, the optimal stake is: (total stake × implied probability of that outcome) / sum of all implied probabilities. Our calculator handles this automatically for any number of outcomes.
In practice, the hardest part of arbitrage isn't the math — it's finding opportunities before they close. Sharp bettors and automated tools monitor hundreds of markets simultaneously. Manual arbitrage bettors typically focus on niches: regional leagues, prop markets, or promotions and boosts that create temporary mispricings. Enhanced odds promotions (bookmaker A boosts a team to 3.00 that normally trades at 2.50) are a reliable arbitrage source, since the other side is available elsewhere at market price.
The main risk isn't losing money — it's account restriction. Bookmakers identify arbitrage bettors by bet timing patterns (always betting late on boosted prices), odd stake amounts (calculated stakes like $47.83 instead of $50), and exclusively betting on mathematically optimal prices. Managing exposure across many bookmakers and mixing arb bets with recreational bets extends account longevity significantly.
The Arbitrage Formula
Implied Sum = Σ(1/Odds_i) Arb exists = Implied Sum < 1.00 Profit % = (1/Implied Sum − 1) × 100 Stake_i = Total Stake × (1/Odds_i) / Implied Sum Payout = Total Stake × (1/Implied Sum)
Frequently Asked Questions
What is arbitrage betting?
Arbitrage betting involves placing bets on all outcomes of an event at different bookmakers where the combined implied probabilities are below 100%. This creates a mathematical lock on profit regardless of the result — hence 'sure bet' or 'surebet'.
Is arbitrage betting legal?
Yes, arbitrage betting is completely legal. Bookmakers may limit or close accounts of identified arbitrage bettors, but it's not illegal. The best approach is to mix arbs with regular bets and avoid obviously calculated stake amounts.
How much profit can I make from arbitrage betting?
Typical arb margins are 1–5% per opportunity. On a $1,000 stake, that's $10–50 per bet. Volume is key — experienced arbers execute 5–20 arbs daily. Monthly returns of 5–15% on invested capital are realistic for dedicated arbers.
Why do arbitrage opportunities exist?
Bookmakers set odds independently based on their risk models. Promotional boosts, slower line updates, different liabilities, and regional market differences all create pricing gaps. Most close within minutes as the market corrects, so speed is essential.