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Matched betting calculator
A matched bet backs a selection at a bookmaker and lays the same selection at a betting exchange. Get the lay stake right and you end up with the same result whatever happens. This calculator works out that lay stake for qualifying bets and free bets.
Back stake, lay stake and liability
Back stake is the amount you bet at the bookmaker. Back odds are the bookmaker's price. Lay odds are the exchange price to lay at, which is normally a little higher. Enter them in decimal, for example 3.1.
Liability is what you lose at the exchange if your selection wins. You need that much in your exchange account before the lay bet can go on. If the selection wins, the bookmaker bet covers it.
A qualifying bet, step by step
Say a bookmaker gives you a £10 free bet when you bet £10. You back a team at 3.0 with your £10. At the exchange, the same team is 3.1 to lay. With 2% commission the calculator says lay £9.74, with a liability of £20.45.
- If the team wins: the bookmaker pays £20 profit and the lay loses £20.45. You're down £0.45.
- If the team doesn't win: the bookmaker bet loses £10 and the lay wins £9.74, less 2%. You're down £0.45.
That small loss is the cost of unlocking the £10 free bet. Laid at 5.0 and 5.2, the free bet then locks in £7.57. Overall you're £7.12 up whatever happens.
| Back odds | Lay odds | Lay stake | Result either way |
|---|---|---|---|
| 2.0 | 2.08 | £9.71 | -£0.49 |
| 3.0 | 3.12 | £9.68 | -£0.52 |
| 4.0 | 4.16 | £9.66 | -£0.53 |
| 5.0 | 5.20 | £9.65 | -£0.54 |
How commission changes the numbers
The exchange takes commission from winning bets only. The calculator builds it into the lay stake, so both outcomes still match.
| Commission | Lay stake | You keep | Of the £10 |
|---|---|---|---|
| 0% | £7.69 | £7.69 | 76.9% |
| 2% | £7.72 | £7.57 | 75.7% |
| 5% | £7.77 | £7.38 | 73.8% |
Mistakes that cost money
- Laying the wrong selection or the wrong market. Check the names match on both sites.
- Leaving a lay bet unmatched. If the exchange price moves, part of your lay may not go through. Check it says matched.
- Getting the bet type wrong. A free bet entered as a qualifying bet gives the wrong lay stake.
- Missing an offer term, such as minimum odds, so the free bet never arrives.
Bookmakers can limit or close accounts that only take offers. Matched betting is legal in the UK, but it's real money on both sides until both bets are settled.
Related calculators
Free bet calculatorLay bet calculatorArbitrage calculator
Read the guide: Matched betting explainedRead →Questions people ask
Is matched betting legal in the UK?
Yes. You're placing normal bets at a bookmaker and an exchange. Bookmakers can restrict accounts they think are only taking offers, though.
Why do I lose a little on qualifying bets?
The lay price is usually a little higher than the back price, and the exchange takes commission. Together they make a small loss, often around 5% of the stake when the prices are close.
What is a lay stake?
The backer's stake you accept at the exchange. If your selection loses, you win the lay stake less commission. If it wins, you pay the liability.
What if the lay odds change before I lay?
Put the new price into the calculator and it gives a new lay stake. The result moves slightly but stays the same in both outcomes.