Arbitrage betting (or "arbing") exploits price differences between bookmakers to guarantee a profit regardless of the outcome. When different bookmakers disagree on the probability of events, their combined odds can sometimes imply less than 100% total probability — creating a risk-free opportunity in theory.
The concept is borrowed from financial markets, where arbitrage involves simultaneously buying and selling the same asset at different prices. In betting, you "buy" all possible outcomes at prices that collectively cost less than the guaranteed payout.
While mathematically elegant, arbitrage betting faces significant practical challenges: odds move quickly, bookmakers impose limits, accounts get restricted, and execution risk can turn theoretical profits into real losses.
Every decimal odd implies a probability. The bookmaker's margin means these typically sum to more than 100%.
Implied Probability = 1 / Decimal OddsAn arbitrage exists when the sum of implied probabilities across all mutually exclusive outcomes is less than 1.
(1/o₁) + (1/o₂) + ... + (1/oₖ) < 1To guarantee the same return regardless of outcome, allocate stakes inversely proportional to the odds:
Stake_i = (Total Stake × (1/o_i)) / Σ(1/o_j)Suppose you find the following best odds across three different bookmakers for a Premier League match:
A 0.45% margin is extremely thin. After considering the time to find and place bets, potential stake limits, and execution risk, this would likely not be profitable in practice. Most viable arbitrages require at least 1-2% margins.
The most common type. Different bookmakers offer better odds on different outcomes, creating an opportunity when combined.
Back an outcome at a bookmaker and lay (bet against) it on an exchange like Betfair. Often appears around market openings.
Betting both sides of a spread or total where the lines differ enough that a specific result wins both bets.
Using sign-up bonuses or free bets to create guaranteed profit. Not pure arbitrage but uses similar hedging principles.
By the time you place your second or third leg, the odds may have shifted. One leg at worse odds can eliminate your profit entirely.
Bookmakers limit stakes on sharp lines. You might only get £20 accepted when you need £500, leaving you with unbalanced exposure.
Bookmakers profile arbers and restrict or close accounts. Consistent small profits across multiple outcomes is a red flag.
Different bookmakers have different rules for abandoned matches, overtime, and void bets. You can win one leg and have another voided.
Most arbs are 1-3%. After exchange commission (2-5%), currency conversion, and withdrawal fees, profit can vanish.
To make meaningful money on 1-2% margins, you need significant capital spread across many bookmaker accounts.
In the 2000s, arbitrage was more viable due to slower odds updates and less sophisticated bookmaker surveillance. Today, odds comparison sites, automated trading bots, and instant stake limits have made pure arbitrage increasingly difficult for retail bettors.
Arbitrage opportunities are detected by continuously comparing odds across bookmakers. The basic algorithm is simple:
Commercial arbitrage services (OddsMatcher, RebelBetting, etc.) automate this process across dozens of bookmakers with real-time updates. However, by the time you see an alert and manually place bets, the opportunity often no longer exists.
- •Professional syndicates with faster infrastructure see and exploit them first
- •Bookmakers' odds compilers monitor for out-of-line prices and correct them
- •The initial arb was a data error or stale price that gets corrected
Instead of guaranteed profit, find bets where your estimated probability exceeds the implied probability. Higher variance but larger edges and fewer restrictions.
Systematically extract value from bookmaker promotions and free bets using hedging. Works while new customer offers last; not sustainable long-term.
Focus on beating the closing line rather than finding arbs. If you consistently get better odds than the final market price, you're likely +EV.
Use exchanges and sharp books (Pinnacle, SBO) that welcome winners. They don't limit accounts, so a genuine edge compounds over time.
This article is educational only and does not constitute betting advice. Arbitrage betting violates the terms of service of many bookmakers and can result in account closure and withheld funds. Always understand the legal and contractual implications in your jurisdiction.