Matched betting calculator.
Matched betting turns bookmaker free bets into near-guaranteed cash by backing a selection at a bookmaker and laying it at an exchange so the bets cancel out. Enter your back odds and stake, your lay odds and the exchange commission, and this free calculator gives you the exact lay stake, your liability, and the profit you lock in whichever way the result goes. Pick qualifying bet or free bet mode below.
Work out your lay
LiveLay stake at the exchange
15.44
exchange liability 64.86
Lay the calculated stake at the exchange to balance both outcomes. A qualifying bet shows a small loss; a free bet shows your locked-in profit. Calculations run in your browser; nothing is stored. For entertainment, not betting advice.
The short answer
What is matched betting?
Matched betting is a way to turn bookmaker free bets and bonuses into near-guaranteed profit. You back a selection at a bookmaker and lay the same selection at a betting exchange, so the two bets cancel out and your result is fixed no matter what happens. By doing this with a free bet, you keep most of its value as cash, usually around 70 to 80 percent.
How to use this calculator
Choose your bet type, enter the back odds and stake from the bookmaker, then the lay odds and commission from your exchange. The calculator returns the lay stake to place, the liability you need in your exchange account, and the profit locked in for each outcome.
There are three modes. Qualifying bet is the bet you place to unlock an offer, and it usually shows a tiny loss. Free bet (stake not returned) is the standard free bet, where only the winnings are paid. Free bet (stake returned) is the rarer kind where the free stake comes back too.
The math
How the lay stake is calculated.
The lay stake is set so your profit is the same whether the selection wins or loses. The formula depends on the bet type, and commission as a decimal (2% is 0.02).
Qualifying bet: lay stake = (back odds × back stake) / (lay odds − commission)
Free bet, stake not returned: lay stake = (back odds − 1) × free bet / (lay odds − commission)
Free bet, stake returned: lay stake = (back odds × free bet) / (lay odds − commission)
Qualifying example. Back 10 at 3.0, lay at 3.2, 2% commission. Lay stake is 9.43, liability 20.75, and both outcomes settle at about a 0.75 loss. That small qualifying loss is the price of unlocking the free bet.
Free bet example. A 20 free bet (stake not returned) at 5.0, laid at 5.4 with 2% commission. Lay stake is 14.87, liability 65.43, and you lock in 14.57 either way, about 73% of the free bet turned into cash.
Use free bets wisely
How much of a free bet do you keep?
Because a free bet does not return its stake, you keep far more of it at long odds than at short ones. This is the single most useful rule in matched betting: save your free bets for bigger prices.
| Back odds (lay matched) | Free bet you keep |
|---|---|
| 2.0 (evens) | about 49% |
| 3.0 | about 66% |
| 4.0 | about 74% |
| 6.0 | about 82% |
| 11.0 | about 89% |
Figures assume the lay odds match the back odds with 2% commission. A 20 free bet returns roughly 10 at evens but closer to 18 at odds of 11.0. Qualifying bets are the opposite: place those at the shortest odds you can to keep the qualifying loss tiny.
Two stages
Qualifying bets vs free bets.
Most offers come in two parts. Understanding the difference is the whole game.
The qualifying bet
This is the real-money bet you place to trigger the offer, for example “bet 10 to get a 20 free bet”. Lay it off to lose only a few pennies. Place it at short odds to keep that qualifying loss as small as possible.
The free bet
Once the free bet lands in your account, you back and lay again to convert it to cash. Because the free stake is not returned, place this one at long odds to keep the most of it, as the table above shows.
The net result
A small qualifying loss plus a larger free-bet profit nets out to a reliable gain per offer. The “bet 10 get 20” example above costs about 0.75 to qualify and returns around 14, for roughly 13 net.
Be straight with yourself
Is matched betting legal and risk-free?
Matched betting is legal, and the math is genuinely low-risk: laying off your bet cancels the gamble, so done carefully you are not really betting at all. The risks are practical, not legal. Mistakes happen, a wrong lay stake or odds that move before you place the second bet can cost you, so double-check every bet.
The bigger thing nobody likes to say: bookmakers do not enjoy losing, and they routinely restrict or “gub” accounts that only bet on offers, cutting your stakes or removing promotions. It is not against the law, but it does limit how long you can do this. Treat it as a way to extract sign-up and reload offers, not a salary. And whatever you do, only ever use money you can afford to lose; if it stops being fun, free confidential help is at BeGambleAware.org.
Questions
Matched betting questions.
What is matched betting?
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Matched betting turns bookmaker free bets and bonuses into near-guaranteed cash. You back a selection at a bookmaker and lay the same selection at a betting exchange, so the bets cancel out and your result is fixed. Using a free bet this way keeps most of its value, usually 70 to 80 percent.
Is matched betting legal?
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Yes, matched betting is legal. You are using publicly offered promotions and placing real bets. It is not fraud or cheating. Bookmakers may not like it and can restrict your account, but using their offers is not against the law.
Is matched betting really risk-free?
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The math is low-risk because laying your bet cancels the gamble. The real risks are human: entering the wrong lay stake, odds moving before you place the second bet, or misreading an offer’s terms. Work carefully and check each bet with this calculator and it stays close to risk-free.
What is a lay bet?
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A lay bet is a bet against an outcome, placed at a betting exchange. Instead of backing a team to win, you lay it, meaning you win if it does not win. Laying your backed selection is what cancels out the bookmaker bet and locks your result.
What is a qualifying loss?
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A qualifying loss is the small amount you lose on the real-money bet placed to unlock an offer. Backing and laying at slightly different odds, plus commission, leaves a tiny gap, usually well under a pound. It is simply the cost of claiming a much larger free bet.
How much can I make from a free bet?
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Typically 70 to 80 percent of the free bet value, as cash. A 20 free bet usually converts to about 14 to 16. The exact figure depends on the odds and commission: longer odds keep more of the free bet, which is why you should use them on bigger prices.
Why should I use free bets on higher odds?
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Because a free bet does not return its stake, only the winnings have value to you, and winnings are a bigger share of the total at long odds. At evens you keep around 49% of a free bet; at odds of 11.0 you keep about 89%. Qualifying bets are the reverse: use short odds to minimise the loss.
About the developer
Jean Borg
Jean builds and maintains every calculator on freecalculators.pro from Malta, with a focus on tools that are fast, free and show their working. This matched betting calculator uses the standard back-and-lay equalising formulas and the figures are verified for accuracy. It is provided for education, not as betting or financial advice. Please bet responsibly. Page last updated June 2026.