Arbitrage Betting Calculator
Free arbitrage calculator (surebet calculator) for 2-way and 3-way markets. Enter the best odds on each outcome and get the exact stake split, guaranteed payout, and locked margin.
American odds as whole numbers (+105, -110); decimal odds with a decimal point (2.05, 150.0). Each outcome should come from the sportsbook offering the best price on that side.
How to Use This Arbitrage Calculator
Find the best available odds on each outcome of the same market at different sportsbooks, enter them above (American or decimal), and set your total stake. The calculator sums the implied probabilities: if they add to less than 100%, an arbitrage exists, and the stake split shows exactly how much to place on each side so every result returns the same payout.
Example: Team A at +105 (DraftKings) and Team B at -102 (FanDuel). Implied probabilities are 48.8% and 50.5%, totaling 99.3%. Staking $1,000 split proportionally locks about $7 whichever team wins. Small, but repeatable, and margins grow when you scan more books and act on fresh lines.
Finding arbs is the hard part
The calculator is the easy 10%. The other 90% is watching every line on every book fast enough to catch windows that close in seconds. That is what SharpAPI's arbitrage API does: automatic cross-book detection across 45+ sportsbooks with sub-second SSE streaming, returning the exact legs, books, and margin for each opportunity. Get a free API key to see live opportunities.
Frequently Asked Questions
What is arbitrage betting?
Arbitrage betting (arbing or surebets) means backing every outcome of one market at different sportsbooks whose combined implied probability is under 100%. Whichever outcome wins, the total payout exceeds the total stake, locking in the difference as margin.
How is an arbitrage bet calculated?
Convert each outcome to decimal odds and sum the reciprocals: 1/odds1 + 1/odds2 (+ 1/odds3 for three-way markets). Under 1.0 is an arb. Stake each outcome proportionally to its reciprocal so every result pays the same amount.
How big are typical arbitrage margins?
Most real arbs run 0.5% to 3% of total stake. Bigger gaps appear around fast line moves, but they close within seconds to minutes, which is why serious arbers use real-time streaming data instead of polling.
Is arbitrage betting risk free?
The math locks a margin, but execution is not risk free: lines move between your bets, a book can void or limit one leg, and stake limits can unbalance the position. It is low risk when executed fast, not zero risk.
How many arbitrage opportunities appear per day?
Scanning across a broad set of US sportsbooks typically surfaces 50 to 200+ cross-book arbitrage windows per day, concentrated around line moves and game starts. More books scanned means more windows found.
Can I automate arbitrage detection?
Yes. SharpAPI detects cross-book arbitrage automatically and returns opportunities with the exact legs, books, and margin via REST or real-time SSE streaming, so you skip building the scanning layer.
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