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Free bet calculator

Turn a bookmaker free bet into money you keep whatever the result. Enter the prices and the calculator gives you the lay stake, the liability and the profit, for the qualifying bet and for the free bet itself.

What are you placing?

Back the free bet at the bookmaker and lay it at an exchange.

Free bet type

Most free bets are stake not returned (SNR): a win pays the winnings only. Check the offer's terms.

At the bookmaker

At the exchange

Smarkets and Matchbook charge about 2%, Betfair Exchange about 5% on most markets. Rates vary by account and market, so check yours.

Result

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Result for each outcome

Which odds keep the most?

The same free bet at other back odds, with the lay price the same percentage above the back price as yours.

Retention at other back odds
Back oddsLay oddsLiabilityProfitRetention
  • Stake not returned: aim for back odds of about 4.0 to 8.0 with a lay price close to the back price. 70–80% retention is good; above 80% is very good.
  • Stake returned: retention barely changes with the odds, so use low odds (around 2.0), where spreads are tight and the liability is small. Expect 90% or more.
  • Higher odds, bigger liability: the exchange holds the liability until the event settles, so make sure your balance covers it. Liquidity is also thinner at long odds.

How the lay stake is worked out

Matched betting pairs a back bet at a bookmaker with a lay bet on the same selection at a betting exchange, where you take the bookmaker's side. If the back bet wins, the bookmaker pays you and you pay the exchange. If it loses, the exchange pays you. The lay stake is chosen so both cases leave you with the same amount. New to exchanges? Read how betting exchanges work first.

With F the free bet, B the back odds, Lo the lay odds and c the commission as a fraction (2% = 0.02):

Stake not returned (SNR): lay stake L = F × (B − 1) / (Lo − c) Stake returned (SR): lay stake L = F × B / (Lo − c) Liability = L × (Lo − 1) Back wins: F × (B − 1) − L × (Lo − 1) [SR: F × B − L × (Lo − 1)] Lay wins: L × (1 − c) Retention = guaranteed profit / F

A worked example

A €10 SNR free bet, backed at 5.0 and laid at 5.2 with 2% commission: L = 10 × 4 / (5.2 − 0.02) = €7.72, with a liability of €32.43. If the back bet wins you get €40 from the bookmaker and pay €32.43 at the exchange. If it loses, the exchange pays €7.72 less 2%. Either way you keep €7.57, a retention of 75.7%. That example is loaded when you open this page.

The qualifying bet

The qualifying bet uses your own money, so the stake comes back when it wins and is lost when it doesn't:

lay stake L = S × B / (Lo − c) Back wins: S × (B − 1) − L × (Lo − 1) Lay wins: L × (1 − c) − S

A €10 qualifying bet at 2.0, laid at 2.06 with 2% commission, needs a lay of €9.80 and loses about €0.39 (3.9%) either way. That small, known loss is the cost of unlocking the free bet. Pick low odds with a close lay price to keep it down.

No exchange: covering with another bookmaker

You can also put the free bet on one outcome and back every other outcome with cash elsewhere, like a sure bet where one leg costs you nothing. Each cash stake is sized to pay what the free bet would pay:

free bet pays R = F × (A − 1) cash stake i = R / O_i profit = R − Σ cash stakes

With a €10 free bet at 4.5 and the other side at 1.30, R = €35, the cash stake is €26.92 and you keep €8.08 (80.8%). For ordinary cash-only sure bets, use the arbitrage calculator.

Before you start

Every offer has terms: minimum odds, which markets count, when the free bet expires and whether it can be split. Read them before you place anything. Bookmakers can also limit or close accounts they see as “bonus abusers”, usually after a run of offers taken and nothing else; our guide to bookmaker limits explains why it happens. Prices can move between your two bets and a lay can go unmatched, so place the bets one after the other and check each price. This page is information, not financial or betting advice. Only bet what you can afford, and stop if it stops being fun.

FAQ

Free bet questions

What is the difference between SNR and SR free bets?
With a stake-not-returned (SNR) free bet, a win pays only the winnings: a €10 free bet at 5.0 pays €40. With a stake-returned (SR) free bet, you also get the €10 back, so it pays €50. Most bookmaker free bets are SNR. Check the offer's terms if you're not sure.
What retention should I expect from a free bet?
For an SNR free bet, 70–80% is good and above 80% is very good. You get there with back odds of roughly 4.0 to 8.0 and a lay price close to the back price. At odds of 2.0 you keep at most about half the free bet, because half of a 2.0 return is the stake you never get back. SR free bets usually keep 90% or more.
What is a qualifying loss?
Most offers need a real-money bet before they give you the free bet. If you lay that bet at an exchange, you lose a little whichever way it goes, because the lay price is usually a bit higher than the back price and the exchange takes commission. A qualifying loss of 1–5% of the stake is typical. The free bet should be worth much more than that.
Which commission rate should I enter?
The rate your exchange charges you on net winnings. Smarkets and Matchbook charge around 2% and Betfair Exchange around 5% on most markets, but rates vary by account, country and market, so check your own. Use 0% only if your exchange really charges nothing.
Can I use a free bet without an exchange?
Yes. Put the free bet on one outcome and back the other outcomes with cash at other bookmakers, sized so every result pays the same. That is the No exchange mode. It often retains more than laying when one bookmaker has a high price on the outcome you need, but you need accounts with enough bookmakers and the price on each leg can move.
Is matched betting risk-free?
The maths locks in the result once both bets are matched at the prices you entered. The risk is in the execution: a price moves before you place the second bet, a lay goes unmatched, you misread the market, or the offer's terms exclude your bet. Bookmakers can also restrict or close accounts they see as bonus abusers. Treat it as information, not advice, and only stake what you can afford.

More free tools

Use your free bets on live sure bets

ArbVantage finds sure bets across 40 bookmakers. Its bet calculator has a free-bet toggle on every leg: switch it on and the stakes are re-solved for a stake-not-returned free bet, so you can see which sure bet keeps the most of it. Free for 14 days.

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