Arbitrage betting is a strategy that takes advantage of different odds offered by different bookmakers. When prices don’t line up correctly, it’s sometimes possible to place bets on all outcomes and secure a small margin no matter what happens.

It’s often called “arbing.” In reality, it’s less about gambling instinct and more about maths and timing. The profits are usually small, but the idea is to remove as much uncertainty as possible from the bet.

That said, it only works if everything is placed correctly — and quickly.

What is Arbitrage Betting?

Arbitrage betting is a method where you back two opposing outcomes to lock in a theoretical margin. Usually, you will be using a traditional bookmaker plus a betting exchange that lets you lay odds as well as back them.

With a lay bet, you are offering odds on a team or player to win. If they don’t win, you keep the other bettor’s stake (minus commission). In essence, you are taking the role of the bookmaker by betting against the gambler. By finding favourable back and lay prices, you may be able to structure the bets so the returns are balanced across outcomes.

You can also use arbitrage betting at bookies with wildly different market odds. In most matches, there will be one favourite and one underdog.

Arbitrage Betting Example

In a Wimbledon tennis match, Player A is priced at 1.90. His opponent, the outsider, is priced at 2.30.

However, another bookmaker may take a different view. They might make the outsider favourite at 1.90 and the favourite as a 2.30 shot.

If you back Player A at 2.30 with the first bookmaker and Player B at 2.30 with the second bookmaker, you’re covering both possible outcomes at the best available prices.

The implied probability of 2.30 odds is 43.48%.
43.48% + 43.48% = 86.96%.

Because that total is under 100%, a theoretical arbitrage opportunity exists.

You would then adjust your stakes so the return is balanced on either outcome. If both bets are accepted at those prices, the result is a small fixed gain.

In practice, prices can change quickly and stakes may be limited, so speed matters.

Example: Back and Lay to Lock in a Margin

Here’s a good example of how you can back two outcomes to ensure a return.

You decide to back Liverpool to win their Premier League game versus West Ham at odds of 2.40. The bet might be at a fixed odds bookmaker or a betting exchange like Betfair. You can also find odds for them NOT TO WIN on the betting exchange at 2.10. When calculated correctly, you can structure both bets to create a small margin across outcomes.

How to Use an Arbitrage Calculator

You can calculate just how much you’ll need to bet by using an arbitrage calculator. You’ll find plenty of these online.

You enter:

• Back odds
• Lay odds
• Exchange commission

The calculator then shows how to split your stakes to balance the return.

In our example, you enter the odds of both outcomes to calculate the potential margin.

Fixed Odds Bet
Liverpool v West Ham (Home win): 2.40
Should stake: £46.01
Potential profit: £64.41

Lay Bet
Liverpool v West Ham (Liverpool NOT to win): 2.10
Should stake: £53.99
Exchange commission: 5%
Potential profit: £56.41

If both bets are matched at those prices, backing both outcomes would result in a profit of £10.42.

Keep in mind that calculators assume both bets are matched at the listed prices. If odds move before you place the second bet, the margin can disappear. That’s one of the main risks.

Arbitrage and Matched Betting

You can also use arbitrage principles in matched betting. Matched betting is a technique where you can take advantage of a bookmaker’s free bet offer. Sign up and make a first real-money wager of your choice. In return, the bookie will award you with a free bet up to the same value. Now you can use arbitrage to lay the same bet on a betting exchange.

When calculated correctly, this approach reduces reliance on chance, though it still depends on accurate staking and following the promotion’s terms.