How this calculator works
A matched bet has two legs. The back bet pays if the selection wins; the lay bet on an exchange pays if it loses. The lay stake is chosen so that the two outcomes produce the same profit, which turns a gambling position into a small, predictable return from a bookmaker offer. The exchange charges commission on the lay winnings, so the stake has to be slightly larger than it would be without commission. The liability is the amount the exchange holds in case the lay bet loses, which is the lay stake multiplied by the lay odds minus one. A free bet changes the arithmetic: with a stake-not-returned free bet you never risk your own money, so the lay stake is based on the profit rather than the full return, and the equal profit is larger. A stake-returned free bet behaves like cash and uses the full-return formula.
Formula
qualifying or stake-returned: lay stake = back stake x back odds / (lay odds - commission). stake-not-returned: lay stake = back stake x (back odds - 1) / (lay odds - commission). liability = lay stake x (lay odds - 1). Profit if the back wins = back return - liability, where the back return is stake x (back odds - 1) for a qualifying or SNR bet and stake x back odds for an SR bet. Profit if the lay wins = lay stake x (1 - commission), minus the back stake for a qualifying bet.
Worked example
A $10 qualifying back bet at 5.0, laid at 5.2 with 2 percent commission, has a lay stake of $10 x 5 / (5.2 - 0.02) = $9.65 and a liability of $40.54. If the back wins the profit is $40.00 - $40.54 = -$0.54, and if the lay wins it is $9.65 x 0.98 - $10 = -$0.54. The same odds on a $10 stake-not-returned free bet give a lay stake of $7.72 and a profit of about $7.57 whichever way it goes.
Advertisement
Frequently asked questions
What are SNR and SR free bets?
SNR means stake not returned: if the free bet wins you keep the winnings but not the stake. SR means stake returned: the stake comes back as cash as well. Most sign-up offers are SNR, and an SR free bet is worth more because its stake behaves like your own money.
Why is the lay stake different for a free bet?
With a qualifying bet you are matching a full return that includes your stake. With an SNR free bet there is no stake to match, so you lay only the winnings. That is why the lay stake is smaller and the profit is larger relative to the free bet size.
What is the liability?
It is the amount the exchange may take from your account if the lay bet wins, which happens when the selection loses at the bookmaker. You need enough balance to cover it even though the matched position is designed to come out even overall.
Is matched betting risk free?
The arithmetic removes the outcome risk, but not every risk. Bookmaker terms can void a bet, odds can move before both legs are placed, accounts can be restricted, and exchanges charge commission. It also requires discipline and record keeping, and in some places the offers or the activity are regulated. Treat this page as a calculator, not as a guarantee of profit.