What is sports betting arbitrage?

An arb, also called a surebet, appears when the best prices across sportsbooks imply less than 100% combined probability. Split the stakes to balance both payouts above the total amount staked.

You don't predict the winner. You use differences between sportsbook prices. Execution and settlement still matter.

Implied probability is 1 divided by decimal odds. Odds of 2.00 imply 50%, 1.50 imply 66.7% and 4.00 imply 25%. This is implied probability, not a measured chance of winning.

At one sportsbook, implied probabilities normally exceed 100%. Over/under at 1.90 / 1.90 totals 105.3%. The excess is the margin built into its prices. Read Sportsbook margin and fair odds.

Combine the best price on each side from different sportsbooks. A total below 100% creates an arb. Calculate the exact return rather than treating the gap to 100% as the profit percentage.

Football, over/under 2.5 goals. The over is 2.10 at one sportsbook, such as Stake, and the under is 2.00 at another, such as Rainbet. Illustrative prices, not a live opportunity.

The stakes follow stake = bankroll × (1 / odds) / sum(1 / odds). A $205 bankroll gives $100 and $105. Change the bankroll and amounts change proportionally. Use the arbitrage calculator.

Sportsbooks price events independently and react at different speeds. Their combined best prices can briefly create a gap.

• Different models and feeds. Sportsbooks use their own models, suppliers and customer adjustments. Prices can diverge on smaller leagues and secondary markets.
• Different reaction times. A lineup, injury or large wager can move one sportsbook before another. That delay can create an opportunity.
• Risk balancing. A sportsbook may raise one side to attract bets against its existing exposure. A competitor with different exposure may keep its price.
• Promotions and errors. Boosts may be intentional; pricing mistakes may be voided under sportsbook rules. See Arbitrage risks.

Price gaps often disappear quickly as the market adjusts. Finding the pair is only the first step: both bets still need to be accepted.

Manual searching means comparing the same markets across several tabs and calculating before prices move. You can do it, but some opportunities last only seconds.

BLAKbets matches events and markets across sportsbooks and shows pairs on the arbitrage board. Odds refresh every 152 ms, with over 44,000 odds scanned and over 143 arbs detected daily. Telegram alerts announce detected opportunities.