What is a Betting Exchange? Smarkets, Betfair & Matchbook

A betting exchange is not a bookmaker. That is the single most important thing to understand. A bookmaker sets the prices and takes the other side of every bet itself. An exchange does neither. It is a peer-to-peer marketplace where punters trade with each other, and the exchange simply takes a small commission on the winnings.

Peer-to-peer, not bookmaker-to-punter

Imagine eBay for sports bets. When you list something on eBay, another user buys it. eBay doesn't own the item and doesn't set the price — it just matches the two parties and takes a cut. A betting exchange works the same way. You post a bet and another user on the platform takes the opposite side of it. The exchange matches you up and handles the money.

This changes everything about how you interact with odds. At a bookmaker you can only back (bet something to happen). At an exchange, every market has two sides — you can back or you can lay. The lay side is what makes matched betting possible, because it lets you cancel out a bookmaker back bet by taking the opposite position elsewhere.

Back and lay, side by side

On an exchange screen, every selection has two prices next to it. The blue number on the left is the best back price: what you would get paid if you backed the selection to win. The pink number on the right is the best lay price: what a backer is currently offering to take on the other side.

These two numbers are always close together but rarely identical. The gap is called the spread and it exists because backers want a slightly higher price than layers are willing to accept. On liquid markets (big football matches, major horse races) the spread is tiny. On obscure markets it can widen out considerably.

Commission replaces the bookmaker margin

Bookmakers make money by offering odds that are slightly worse than the true probability of each outcome. That margin (often called the “overround”) is baked into every price you see. Exchanges do not have this margin because they are not taking the other side of your bet. Instead, they charge a small commission on the winnings of whichever punter called it right.

On the big three UK exchanges that commission is 2% in most cases. It is deducted automatically when the market settles, so you do not need to calculate it manually, but your matched betting calculator does need the right commission rate in its commission field.

The three main UK exchanges

Three exchanges matter in the UK market in 2026. They all do the same job but have different strengths.

Smarkets

Flat 2% commission for every user, a clean and genuinely beginner-friendly interface, and UK-focused markets. Liquidity is solid on Premier League football, major horse racing and tennis. For a brand new matched bettor, Smarkets is the exchange we recommend opening first — our Smarkets guide walks through the sign-up process.

Betfair Exchange

The largest exchange in the UK and the one with by far the deepest liquidity, especially on minor markets, in-play football and anything obscure. Base commission is 2%, but long-term winners may eventually be subject to Betfair's Premium Charge on very high lifetime profits. For most matched bettors that threshold is far away. See our Betfair Exchange guide for the specifics.

Matchbook

The underdog, but genuinely useful. Base commission is 2%, and Matchbook regularly runs promotional periods with 0% commission on certain sports — horse racing is the most common. When those promotions are active, Matchbook can comfortably be the best exchange to use for particular markets. Liquidity is lower than Smarkets or Betfair, so always check the spread before committing. Our Matchbook guide covers the welcome offer.

Which exchange should you open first?

Smarkets. Every time, for a complete beginner. The interface is by far the most approachable, commission is predictable, liquidity is fine for the kind of mainstream football, horse racing and tennis markets you will be using on welcome offers, and the welcome offer itself is straightforward. Once you have a handful of offers under your belt you can open Betfair as your second exchange to get access to its deeper liquidity on minor markets. Matchbook is a nice-to-have third step, particularly useful around horse racing promotions.

If you are actively picking between Smarkets and Betfair, our dedicated comparison post goes deeper: Smarkets vs Betfair Exchange.

Exchanges and matched betting

An exchange is not somewhere you go to make money on its own. It is a tool — the place where you balance out the bookmaker side of a matched bet by placing a lay at matching odds. If you have not yet read about lay betting, start there. Our lay betting explainer covers exactly what happens on the exchange side of a matched bet.