Become the Bookmaker on Betfair: Guide to Locking in Guaranteed Profits

If you’ve ever wondered how traditional bookmakers always seem to turn a profit, you’re not alone. The secret lies in a fundamental principle called bookmaking—the process of laying all outcomes on an event to lock in a guaranteed profit, no matter what happens.

This was the very first Betfair strategy I learned. It’s a simple, ultra-low-risk approach that won’t make you rich on a single trade, but the steady accumulation of small, winning trades is incredibly powerful for building your trading bank. It was instrumental in growing mine for a good 6-12 months when I first started. For anyone looking to understand the fundamentals, learning how to be a bookmaker on Betfair is the perfect starting point.

This guide will take a deep dive into this beginner-friendly method for winning small but regular profits on the sports exchange. We’ll break down the fundamental principles and show you, step-by-step, how to “make a book” successfully.

What It Truly Means to Be a Bookmaker on Betfair

It’s important to clarify what we mean. You are not becoming a licensed, high-street bookmaker. Instead, you are using the “lay” function on the Betfair Exchange to replicate the core profit-making mechanism of a bookmaker within a peer-to-peer marketplace. This is the essence of being a bookmaker on Betfair.

Traditional Bookmaker (Sportsbook): A company sets the odds with a built-in profit margin (the “overround”). You can only “back” an outcome.
Betfair Exchange: A peer-to-peer platform where you bet against other users. This allows you to:
- Back: Bet on something to happen (like a traditional bet).
- Lay: Bet against something happening (acting as the bookmaker for that bet).

Bookmaking on the exchange is the art of laying every possible outcome in a market at odds that guarantee you a profit overall. This strategy is the foundation for anyone who wants to learn how to become a successful bookmaker on Betfair.

The Core Principle: Understanding the “Perfect Book” and Overround

Understanding the fundamental principles behind the ‘book’ is crucial to understanding how to ‘make a book’ successfully.

The Perfect Book:
In a fair world, the probabilities of all outcomes in an event add up to 100%. A tennis match is the perfect example: Player A wins or Player B wins. We know with 100% certainty that one of them will win. If you could lay both players at their true probability, the sum of your liabilities would equal the stakes you take in, leaving you with zero profit.

The Overround: The Bookmaker’s Profit
This is where the magic happens. A bookmaker never offers odds that reflect the true 100% probability. Instead, they shorten the odds, building in a profit margin called the overround (or “vig”). The goal of a bookmaker on Betfair is to create a personal overround within the exchange market.

Imagine that tennis match again. The true probability might be:

Player A: 50% (Decimal Odds: 2.0)
Player B: 50% (Decimal Odds: 2.0)
Total Probability: 100%

A bookmaker will offer odds worse than this, say:

Player A: 1.90
Player B: 1.90
Total Probability: (100/1.9) + (100/1.9) = 52.63% + 52.63% = 105.26%

This 5.26% overround is their guaranteed profit. This is how traditional bookmakers have always operated.

Your Advantage on Betfair:
On the Exchange, the overround is typically much smaller because it’s driven by market sentiment, not a corporate profit target. Your goal as a bookmaker on Betfair is to lay outcomes in such a way that the implied probability of all your lay bets adds up to less than 100%, creating your own personal overround and a locked-in profit.

Step-by-Step: How to Make a Book on a Tennis Match

Tennis is ideal for beginners due to its two-outcome nature. Let’s walk through a practical example of how a bookmaker on Betfair would operate.

The Match: Emma Raducanu vs. Leylah Fernandez
The Goal: Lay both players at odds that create a combined implied probability of under 100%.

Step 1: Find the Market & Assess Odds
You check the Match Odds market on Betfair before it starts.

You can Lay Raducanu at 2.10
You can Lay Fernandez at 2.10

Step 2: Calculate the Implied Probability
Implied Probability = (1 / Decimal Odds) * 100

Lay Odds for Raducanu (2.10): (1 / 2.10) * 100 = 47.62%
Lay Odds for Fernandez (2.10): (1 / 2.10) * 100 = 47.62%
Total Implied Probability: 95.24%

This is an underround! The market is offering odds that add up to less than 100%. This is your opportunity to make a book.

Step 3: Place Your Lay Bets (Using Software)
You decide you want to make a total profit of £10, regardless of the winner. Manually calculating stakes is complex and error-prone. This is where professional trading software is essential for any aspiring bookmaker on Betfair.

Using software like Bet Angel, you would:

Lay one player for a set stake.
The software’s “Dutching” or “Green Up” tool instantly shows you the required lay stake on the other player to lock in an equal profit (e.g., £10) on both outcomes.
You place the second bet, and your profit is guaranteed before the match even begins.

The Final Outcome with Software:
After correctly placing the lays with software-calculated stakes, the result is:

If Raducanu wins: You make a profit of £10.
If Fernandez wins: You make a profit of £10.

You have successfully acted as the bookmaker on Betfair. Your profit is locked in the moment both bets are matched.

Why You Need Automation Software

As demonstrated, calculating stakes manually is complex and risky. Professional trading software is non-negotiable for efficient bookmaking.

Bet Angel – The Professional’s Choice: Its “Dutching” tool automatically calculates stakes to lock in a specific profit across multiple outcomes. This is perfect for anyone serious about becoming a bookmaker on Betfair.
- Link: Bet Angel
Geeks Toy – The Popular Favorite: Also offers excellent one-click tools for balancing your book and ensuring a guaranteed green profit.
- Link: Geeks Toy
Betfair Bot Manager – For Automation: You can set up bots to automatically identify underround markets and place the necessary bets to make a book.
- Link: Betfair Bot Manager

Important Considerations and Risks

Market Selection: This strategy works best on two-outcome markets like Tennis, Boxing, or the Draw No Bet market in football. I wouldn’t try it on horse racing due to the multitude of runners.
Pre-Market Only: This is a pre-event strategy. Never attempt it in-play, as odds can move too fast.
Liquidity is Key: You need enough money in the market to get all your lay bets matched at the desired odds.
Commission: Remember, Betfair charges commission on your net winnings in a market. Always factor this in.
The Goal is Small, Consistent Profits: Don’t expect huge returns. The power of this strategy is in its low-risk, repetitive application to build your bankroll steadily.

Your Action Plan to Get Started

Education First: Understand implied probability and overround/underround.
Get Software: Download the free version of Bet Angel or Geeks Toy. Practice using the Dutching or Green Up functions in their practice modes.
Find a Suitable Market: Look for a two-outcome market with high liquidity.
Start Small: Use your software to identify an opportunity and place small bets to test the process. Aim to lock in a profit of just £1 or £2. The goal is to learn the mechanics.
Analyze and Refine: Review your results and gradually scale up as your confidence grows.

The Final Word

Learning to be a bookmaker on Betfair is a foundational trading strategy that teaches crucial lessons about risk, probability, and market mechanics. It empowers you to step into the role of the house and secure profits before a ball is even kicked or a serve is hit.

While the profits from individual trades are small, their consistency is what makes this strategy so valuable for building a foundation. Arm yourself with the right software, start small, and focus on the process. The steady accumulation of guaranteed wins is a powerful way to grow your trading bank and your confidence.

Disclaimer: This blog post is for informational and educational purposes only. Trading on the Betfair Exchange involves financial risk. It is your responsibility to ensure that your activities are legal in your jurisdiction. Please gamble responsibly and seek help if you feel you may have a gambling problem. You must be 18+ to participate. Past performance is not indicative of future results.