Arbitrage Calculator
Find guaranteed profit opportunities by comparing odds across different bookmakers. Enter the odds for each outcome, and the calculator will instantly tell you whether an arbitrage opportunity exists and how to distribute your stake.
Total amount to distribute across all outcomes
Strong Arb (3-Way)
H: 1.95 | D: 4.20 | A: 4.50
Guaranteed profit
No Arb (3-Way)
H: 2.10 | D: 3.30 | A: 3.40
Over 100% implied probability
2-Way Arb
O1: 2.15 | O2: 1.95
Simple 2-outcome arb
What is Arbitrage Betting?
Arbitrage (or "arbing") is placing bets on all outcomes of an event across different bookmakers so that you guarantee a profit regardless of the result. It works when combined odds imply less than 100% probability.
How are Stakes Calculated?
Stakes are distributed so that every outcome returns the same amount. Each stake is proportional to the inverse of its odds divided by the total implied probability, ensuring equal profit no matter which outcome wins.
What is Arbitrage Betting?
Arbitrage betting (also called "arbing" or "sure betting") is a strategy where you place bets on all possible outcomes of an event across different bookmakers, guaranteeing a profit regardless of the result. This is possible when the combined implied probabilities from different bookmakers sum to less than 100%.
For example, if Bookmaker A offers 2.15 on Team 1 to win and Bookmaker B offers 1.95 on Team 2, the total implied probability is (1/2.15 + 1/1.95) = 46.51% + 51.28% = 97.79%. Since this is below 100%, an arbitrage opportunity exists with a guaranteed profit of approximately 2.21% of your total stake.
Arbitrage opportunities arise because bookmakers set odds independently and may have different opinions on the probability of outcomes. While individual margins make each bookmaker profitable, the differences between bookmakers can create windows of risk-free profit for informed bettors.
How to Use the Arbitrage Calculator
Step 1: Select Market Type
Choose between a 3-way market (e.g., football match result: Home Win/Draw/Away Win) or a 2-way market (e.g., tennis match winner, over/under goals). 3-way markets offer more arb opportunities because there are more outcomes to compare.
Step 2: Enter Your Total Stake
Set the total amount you want to distribute across all outcomes. The calculator will split this optimally so that every outcome returns the same profit. A typical starting stake is £100.
Step 3: Enter Odds from Different Bookmakers
Input the best decimal odds you can find for each outcome. Use different bookmakers for each outcome to find the highest odds. Optionally enter the bookmaker name for each to keep track of where to place each bet.
Step 4: Review Your Results
The calculator instantly shows whether an arbitrage exists (green badge) or not (red badge), along with the exact stake for each outcome, guaranteed profit, and ROI. If an arb exists, place your bets quickly before the odds change.
How Arbitrage Betting Works
1. Find Odds Discrepancies
Compare odds across multiple bookmakers for the same event. The key is finding the highest odds for each outcome from different providers. Odds comparison websites can speed up this process significantly.
2. Check for an Arbitrage Opportunity
Calculate the total implied probability by summing 1/odds for each outcome. If the total is below 100% (or 1.0 as a decimal), an arb exists. The difference below 100% is your profit margin.
3. Distribute Stakes Optimally
Each stake is calculated as: Stake = Total Stake x (1/Odds) / Total Implied Probability. This ensures every outcome produces the same return, giving you a guaranteed profit regardless of the result.
4. Place All Bets Simultaneously
Speed is critical. Place all bets as quickly as possible before odds change. Even a small odds movement can eliminate the arb. Have accounts funded and ready at multiple bookmakers before you start.
Risks and Considerations
Odds Movement
Odds can change between placing your first and last bet. If odds move against you, the arb may disappear or even result in a loss. Always place bets as quickly as possible.
Account Restrictions
Bookmakers may limit or close accounts they suspect of arbing. Vary your betting patterns, use multiple bookmakers, and avoid consistently taking the highest odds on every market.
Maximum Stake Limits
Bookmakers may not accept the exact stake you need. If your bet is partially filled or rejected, the arb may not work. Check maximum bet limits before relying on the calculated stakes.
Palpable Errors
Sometimes extremely favourable odds are pricing errors (palpable errors). Bookmakers reserve the right to void bets placed on palpable errors, potentially leaving you exposed on other legs.
Frequently Asked Questions
What is an arbitrage bet?
An arbitrage bet (or "sure bet") is when you place bets on all possible outcomes of an event across different bookmakers at odds that guarantee a profit regardless of the result. It exploits price differences between bookmakers.
How do I know if an arbitrage opportunity exists?
An arb exists when the total implied probability (sum of 1/odds for each outcome) is below 100%. For example, if three outcomes have implied probabilities of 48%, 24%, and 23%, the total is 95% — meaning a 5% arb exists.
Is arbitrage betting legal?
Yes, arbitrage betting is completely legal. You are simply placing bets at the best available odds. However, bookmakers are private businesses and may choose to restrict accounts that consistently exploit arb opportunities.
How much profit can I expect from arbitrage?
Typical arb margins are 1-5% of your total stake. With a £1,000 total stake and a 3% arb, you would guarantee £30 profit. While individual profits are small, they add up with volume and are risk-free.
Why do arbitrage opportunities exist?
Bookmakers set odds independently based on their own risk models and customer base. Differences in opinion, reaction speed to news, and balancing their own books create windows where combined odds fall below 100%.
How quickly do arb opportunities disappear?
Most arbs last only minutes, sometimes seconds. Bookmakers use automated systems to monitor and adjust odds. You need to act fast, have pre-funded accounts, and ideally use software to detect opportunities in real time.
Can I use betting exchanges for arbitrage?
Yes, betting exchanges like Betfair are excellent for arbing because you can both back and lay outcomes. Remember to account for exchange commission (typically 2-5%) in your calculations, as it reduces your profit margin.
What is the difference between arbitrage and value betting?
Arbitrage guarantees a profit by covering all outcomes. Value betting only backs outcomes where you believe the true probability is higher than the bookmaker implies — it offers higher long-term returns but carries risk on individual bets.