Betting maths guide
What Is Matched Betting?
Matched betting is a betting method that uses bookmaker offers and exchange lay bets to try to reduce risk and convert promotions into a more predictable result.
How does matched betting work?
Matched betting normally uses two sides of a market: a back bet with a bookmaker and a lay bet on a betting exchange. The lay bet is used to reduce the risk of the back bet.
Many matched betting examples involve bookmaker offers. A common structure is: place a qualifying bet, receive a free bet, then convert the free bet into a more predictable amount using an exchange lay bet.
The basic matched betting process
- Find a bookmaker offer with clear terms.
- Place the qualifying back bet with the bookmaker.
- Lay the same selection on an exchange.
- Receive the free bet if the offer conditions are met.
- Use the free bet on a suitable market.
- Lay the free bet selection on an exchange.
- Calculate the overall result after commission.
Back bet and lay bet in matched betting
A back bet is the normal type of bet where you bet on something to happen. A lay bet is where you bet against that same outcome happening.
| Bet type | Placed where? | What you want to happen? |
|---|---|---|
| Back bet | Bookmaker | You want the selection to win. |
| Lay bet | Betting exchange | You want the selection not to win. |
When the back bet and lay bet are calculated correctly, the result can be balanced so that the outcome is similar whether the selection wins or loses.
Qualifying bet example
A qualifying bet is the bet placed to trigger an offer. For example, a bookmaker might offer a £30 free bet after you place a £10 qualifying bet at minimum odds.
| Qualifying stake | Back odds | Lay odds | Commission | Possible qualifying loss |
|---|---|---|---|---|
| £10 | 2.00 | 2.02 | 2% | About £0.10 |
The qualifying bet may create a small loss, but it can unlock the free bet. The overall value depends on both parts of the offer.
Free bet conversion example
Suppose the qualifying bet gives you a £30 stake-not-returned free bet. You use the free bet at back odds of 5.00 and lay it at 5.20 with 2% exchange commission.
| Free bet stake | Back odds | Lay odds | Commission | Estimated free bet result |
|---|---|---|---|---|
| £30 | 5.00 | 5.20 | 2% | About £22.70 |
If the qualifying bet cost around £0.10 and the free bet converts to around £22.70, the estimated overall result is around £22.60 before considering any other practical issues.
Matched betting formula
The exact calculation depends on the offer type, but many basic matched betting examples use these formulas.
Qualifying lay stake = qualifying stake × back odds ÷ (lay odds − commission)
Stake-not-returned free bet lay stake = free bet stake × (back odds − 1) ÷ (lay odds − commission)
Overall result = qualifying result + free bet result
The free bet formula changes depending on whether the stake is returned or not returned.
Matched betting risks and practical issues
Matched betting is often described as low risk, but it is not risk-free. The maths can reduce exposure, but practical issues still matter.
- Human error: entering the wrong stake or odds can create a loss.
- Odds movement: the exchange price can move before the lay bet is matched.
- Liquidity: there may not be enough money available at the required lay odds.
- Commission: exchange commission reduces winnings.
- Offer terms: minimum odds, market restrictions and expiry dates matter.
- Account restrictions: bookmakers may restrict promotions or limit accounts.
- Settlement differences: bookmaker and exchange rules may not always match perfectly.
Is matched betting the same as arbitrage?
Matched betting and arbitrage are related because both can involve covering outcomes with back and lay bets. But they are not exactly the same.
| Method | Main idea | Typical source of value |
|---|---|---|
| Matched betting | Use offers and lay bets to reduce risk. | Bookmaker promotions and free bets. |
| Arbitrage | Cover all outcomes when prices create an underround. | Price differences across markets. |
Arbitrage usually depends on the odds alone. Matched betting often depends on promotional value from a free bet or bonus.
Common matched betting mistakes
Using the wrong free bet type
A stake-not-returned free bet needs a different calculation from a stake-returned or cash-style bet.
Ignoring lay liability
The lay stake is not the same as the amount at risk. Lay liability is what you may need to pay if the selection wins.
Forgetting minimum odds
If the qualifying bet or free bet does not meet the minimum odds, the offer may not count.
Not checking market rules
Settlement rules can vary by bookmaker and exchange. This matters in racing, player markets, void bets and abandoned events.
Thinking matched betting removes all risk
Matched betting can reduce risk when calculated correctly, but it does not remove mistakes, rule differences, restrictions or gambling risk.
Matched betting FAQs
What is matched betting in simple terms?
Matched betting is a way of using bookmaker offers and exchange lay bets to try to reduce risk and convert promotions into a more predictable result.
What is a qualifying bet?
A qualifying bet is the bet placed to trigger an offer, such as a free bet.
What is lay liability?
Lay liability is the amount you risk on the exchange if the selection you lay wins.
Does matched betting guarantee profit?
No. The calculations may show a positive expected result, but practical issues and mistakes can still create losses.
Which calculator should I use?
Use the Matched Betting Calculator for a qualifying bet plus free bet. Use the Free Bet Calculator if you only want to calculate a free bet conversion.