A betting exchange is a platform where you bet against other people rather than against a bookmaker. For matched betting, exchanges are essential because they let you lay bets — betting that an outcome will NOT happen — which is the second half of every matched bet.
Betfair vs Smarkets — which should you use?
Betfair is the largest exchange in the world with the highest liquidity — meaning you can always find someone to match your bet. Smarkets charges lower commission (2% vs Betfair's 2–5%) and has a cleaner interface. Most matched bettors use both.
- Betfair: Higher liquidity, wider market range, welcome offer available
- Smarkets: Lower commission, simpler interface, competitive odds
- Both are UK-regulated and trusted
What is a lay bet?
When you lay a bet, you are acting as the bookmaker. You are saying "this outcome will NOT happen." If it doesn't happen, you keep the backer's stake. If it does happen, you pay out at the lay odds.
Understanding lay liability
Lay liability is the amount you must have in your exchange account to cover a potential loss on a lay bet. For example: laying £10 at odds of 3.0 means your liability is £20 (£10 × (3.0 − 1)). Your matched betting calculator always shows the exact liability.
Step-by-step: placing your first lay bet
- Go to the exchange and find the same event you have backed at the bookmaker.
- Click on the lay (pink) side of the market for the same selection.
- Enter the lay stake as shown by your matched betting calculator.
- Check the liability shown — make sure you have sufficient funds.
- Confirm the bet.
Exchange commission
Exchanges charge commission on winnings, not on every bet. Betfair charges 2–5% depending on your market base rate; Smarkets charges 2%. The matched betting calculator factors commission in automatically when calculating your lay stake.
Calculate the correct lay stake and see your expected profit for any offer.
Use the Calculator →