Work out your lay stake, liability and profit in seconds. Built for qualifying bets and free bets — the two situations that cover 90% of matched betting.
A regular real-money bet placed to unlock a promotion. You want to lose as little as possible — ideally break even.
Your profit or loss in each scenario. Matched betting works when both bars are equal — either a small controlled loss (qualifier) or a guaranteed profit (free bet).
The market's view of the chance this outcome happens. The gap between back and lay is the spread — tighter is better.
Matched betting uses free bets and promotions from bookmakers and covers the same event with an opposite bet (a lay) on a betting exchange. Whatever happens, the result is roughly the same — a small loss on the qualifier, then a guaranteed profit once the free bet triggers. This calculator does the maths so you don't.
A lay bet is a bet against an outcome. You place it on a betting exchange (Betfair, Smarkets, Matchbook). If the outcome doesn't happen, you win the other backer's stake; if it does, you pay out at the lay odds. Laying covers your back bet at the bookmaker.
SNR (Stake Not Returned) is the standard free bet: if it wins, you only get the winnings, not the stake back. SR (Stake Returned) is rarer and behaves like a normal bet — stake comes back on a win. Each needs a different lay stake, which is why this calculator has a mode for each.
For qualifiers and SR free bets: (back stake × back odds) / (lay odds − commission). For SNR free bets: (back stake × (back odds − 1)) / (lay odds − commission). The commission term is 1 − (commission% / 100) applied to the lay odds effective return.
The amount the exchange holds from your balance to cover the lay bet if it loses. Formula: lay stake × (lay odds − 1). You need this much free in your exchange account to place the bet.
That's normal and expected. Back and lay odds rarely match exactly — the gap between them is the qualifying loss, and it's the cost of unlocking a bigger free bet. A tight back/lay match (low odds spread) keeps that loss small.
Copy the back odds from the bookmaker's page (Bet365, William Hill, Paddy Power…) and the lay odds from an exchange (Betfair Exchange, Smarkets). Oddschecker is useful to spot where the gap is tightest.
This tool is for informational and educational purposes. Matched betting is legal in the UK, Ireland and Australia but tax and eligibility rules vary by jurisdiction. Gambling can be addictive — please gamble responsibly. 18+. No affiliation with any bookmaker or exchange.