Matched Betting Calculator

Calculate the exact lay stake on the exchange to cover any bookmaker bonus. Works with real money (qualifying bet) and free bets. 100% free.

Bet type

Enter your data

Bookmaker odds (back) The odds at the bookmaker (e.g.: 2.50)

Exchange odds (lay) The odds you bet against on the exchange (e.g.: 2.60)

Stake amount How much you'll bet at the bookmaker (e.g.: $10)

Exchange commission (%) Commission charged by your exchange (Betfair: 2-5%)

Free bet type

SNR (Stake Not Returned) Most common. You only receive winnings, not the stake

SR (Stake Returned) You receive stake + winnings (uncommon)

Result

                    Bet on exchange (lay stake)
                    $9.69
                

Required in exchange (liability) $15.51

If your bet wins -$0.85

If your bet loses -$0.85

Controlled loss (qualifying loss) $0.85

Guaranteed profit — $

Extraction rate — %

This is the small loss you accept to access the bonus. Recovered with surplus when betting the free bet in the next step.

Practical step-by-step example

Let's see how this applies to a real offer. Imagine this typical bonus:

Bet at the bookmaker

You stake $10 on Real Madrid at FanDuel at odds of 2.50.

This is the qualifying bet — needed to activate the bonus.

Cover on the exchange

You bet $9.69 against Real Madrid on Betfair Exchange at odds 2.60 (2% commission).

This covers the opposite outcome — if Madrid loses, you win here.

Qualifying result

Whatever happens with the match, you'll have a small controlled loss of ~$0.85. It's the cost of "opening the door" to the bonus.

🔴 Qualifying loss: -$0.85 (small necessary loss)

Receive the $30 free bet

FanDuel credits you the $30 in free bets after settlement of your qualifying bet.

Switch the calculator above to "🎁 Free Bet" mode

Bet the free bet and cover

Use the $30 free on a new bet (high odds, e.g.: 5.00) and cover on the exchange as the tool calculates.

🟢 Guaranteed profit: ~$24 (you extract 80% of the bonus value)

Final result

Gross profit: $24 - $0.85 qualifying loss = $23.15 net guaranteed, risk-free. And all this on an event you don't even have to follow.

Why does this work?

Bookmakers offer bonuses to attract customers. Their hope is you bet the bonus and lose (because most bet randomly). Matched betting exploits these bonuses risk-free using an exchange to cover the opposite outcome.

The math guarantees you extract 75-85% of each bonus's nominal value, regardless of the event outcome. It's not cheating, not illegal, not sports prediction — it's pure algebra applied to the betting market.

Want to skip the manual work?

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Formulas this calculator uses

For maximum transparency, these are the exact mathematical formulas the calculator applies. Same as NinjaBet, OddsMonkey, and any other tool in the sector.

Real Money Mode (Qualifying Bet):

lay_stake = (back_stake × back_odds) / (lay_odds − commission)

Free Bet Mode (SNR — Stake Not Returned, most common):

lay_stake = (back_stake × (back_odds − 1)) / (lay_odds − commission)

Free Bet Mode (SR — Stake Returned, rare):

lay_stake = (back_stake × back_odds) / (lay_odds − commission)

Limitations of this calculator

This calculator is functional and mathematically correct, but has limitations inherent to a free tool:

It doesn't search for odds automatically. You have to manually input back and lay odds after checking each site.
It doesn't detect active offers. You have to keep yourself updated on which bookmakers have bonuses available now.
No Oddsmatcher included. Professional tools (NinjaBet, OddsMonkey) have an automatic comparator telling you exactly which odds to use to minimize qualifying loss.
No Profit Tracker. You have to keep your own log of each bonus executed.

If you do matched betting occasionally, this calculator is enough. If you want to do it professionally and maximize income, a tool like NinjaBet automates all of the above for ~$30/month.

Frequently asked questions

Is it legal to use this calculator?

Yes. The calculator just applies basic math to odds. What's legal or not is matched betting itself, which is 100% legal in most countries and taxable as capital gains.

Why is there a loss in the qualifying bet?

Because back and lay odds are never exactly equal — there's always a small spread. That difference, plus exchange commission, generates the controlled "qualifying loss". The closer the odds are, the smaller this loss (ideal: odds differing by less than 0.05).

Which odds should I use to minimize the loss?

Always look for events where back and lay odds are as close as possible. Ideally difference ≤ 0.05 (e.g.: back 2.50 and lay 2.55). Professional tools like NinjaBet do this search automatically with their Oddsmatcher.

What if the free bet is SR instead of SNR?

SR (Stake Returned) free bets are rare but more profitable — you receive stake + winnings. SNR (Stake Not Returned) are standard: you only receive winnings. The calculator automatically changes the formula based on the type you select.

Why do I need an exchange? Isn't the bookmaker enough?

The exchange (Betfair, Smarkets, Matchbook) is where you can bet AGAINST an outcome. At traditional bookmakers you can only bet FOR. Without an exchange you couldn't cover the opposite outcome and therefore couldn't do risk-free matched betting.

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