Work out your lay stake, liability, and qualifying loss instantly — for normal bets, free bets (SNR/SR), and risk-free bets. No signup needed.
A matched betting calculator works out the lay stake you need to place on a betting exchange to cancel out a "back" bet placed with a bookmaker — leaving you with a small, known qualifying loss (or a locked-in profit, when using a free bet). Instead of doing the maths by hand, you enter your back stake, back odds, lay odds, and commission, and the calculator does the rest instantly.
Choose your bet type — Normal for a qualifying bet, or Free Bet (SNR/SR) and Risk Free for offer-specific calculations. Enter your back stake and back odds from the bookmaker, then your lay odds and commission from the exchange (e.g. Betfair or Smarkets). The calculator shows your lay stake, liability, and the outcome if either side wins.
Three figures matter most once you calculate a bet: your lay stake, your liability, and your qualifying loss (or profit, for free bets). For a normal qualifying bet, the lay stake is worked out so that your result is roughly the same whether the back bet wins or loses:
Your liability — the amount you'd owe the exchange if the back bet wins — is your lay stake multiplied by the lay odds minus one. You need this amount available in your exchange account before placing the lay bet, since it's the exchange's way of covering your side of the bet.
Here, whichever way the event goes, you end up losing roughly 58p — a small, known cost to unlock whatever free bet or offer is tied to that qualifying bet. That's normal, and it's what the calculator above is working out for you automatically.
This calculator supports four bet types, each with a slightly different formula depending on how the offer pays out:
A standard qualifying bet using your own money on both sides. You'll take a small, predictable qualifying loss — this is the bet you place to unlock most free bet offers.
Stake Not Returned. If the back bet wins, you keep the winnings but not the stake. Because you're not risking real money, the lay stake and formula are different to a normal bet.
Stake Returned. If the back bet wins, you get the winnings and the stake back. These are rarer and worth more than SNR free bets, so they extract more profit when laid off.
If the back bet loses, the bookmaker refunds your stake (often as a free bet, sometimes partially). The calculator factors in the refund amount and retention rate to size your lay stake correctly.
Choose your bet type — Normal for a qualifying bet, or Free Bet (SNR/SR) and Risk Free for offer-specific calculations. Enter your back stake and back odds from the bookmaker, then your lay odds and commission from the exchange (e.g. Betfair or Smarkets). The calculator shows your lay stake, liability, and the outcome if either side wins — updating live as you type, so you can test different odds before placing anything.
The lay stake is the amount you bet against an outcome on a betting exchange, sized so that your profit or loss is roughly the same whether your back bet with the bookmaker wins or loses.
Liability is the amount you would owe the exchange if your back bet wins. It's your lay stake multiplied by your lay odds minus one, and it needs to be available in your exchange account before you place the lay bet.
A small qualifying loss is normal and expected. It comes from the gap between your back and lay odds plus exchange commission, and is the cost of unlocking the free bet or offer tied to that bet.
SNR (Stake Not Returned) free bets pay out winnings only if the bet wins. SR (Stake Returned) free bets pay out winnings plus your stake. SR free bets are worth more and are laid differently as a result.
Yes — it's completely free and doesn't require an account or signup. Creating a free GreenUp account lets you also log and track every bet you calculate here.
This calculator is free to use with no account needed. If you're placing matched bets regularly, GreenUp lets you log every bet, track your bankroll across bookmakers and exchanges, and see your overall profit — automatically, without spreadsheets.
Read our beginner's guide to matched betting, or learn more about how qualifying loss is calculated.