Matched Betting Calculator
Calculate the lay stake and liability to match a bookmaker back bet at an exchange, with commission: qualifying bets and free bets (stake not returned or returned), with profit either way.
How it works
qualifying bet & free bet (stake returned): lay stake = back stake × back odds ÷ (lay odds − commission) · free bet SNR: lay stake = back stake × (back odds − 1) ÷ (lay odds − commission) · liability = lay stake × (lay odds − 1) · profit if lay wins = lay stake × (1 − commission) − back stake (qualifying) or lay stake × (1 − commission) (free bet)
Matched betting backs an outcome at a bookmaker and lays the same outcome at a betting exchange, so one bet's win cancels the other's loss. The lay stake that balances both sides depends on the odds and the exchange commission. A qualifying bet usually loses a little (the gap between back and lay odds plus commission); the free bet that a sign-up or reload offer then gives is turned into most of its value — typically 70–80% for a stake-not-returned free bet at higher odds. Liability is the money the exchange holds in case the lay bet loses.
Worked example
A $10 qualifying bet backed at 3.00 and laid at 3.10 with 2% commission needs a lay stake of $10 × 3.00 ÷ (3.10 − 0.02) = $9.74 and a liability of $20.45. If the back bet wins you net $20.00 − $20.45 = −$0.45; if the lay wins you net $9.55 − $10.00 = −$0.45, a qualifying loss of 4.55%.
Sources: Wikipedia — Matched betting · GamCare — Support
Frequently asked questions
How do you calculate a lay stake?
Lay stake = back stake × back odds ÷ (lay odds − commission). For a stake-not-returned free bet use (back odds − 1) instead of back odds, because the free stake does not come back with the winnings.
What is liability in lay betting?
The amount you pay out if the outcome you laid wins: lay stake × (lay odds − 1). You need at least this in your exchange account before the lay bet can be placed.
Is matched betting legal and tax-free?
It is legal in many countries because you are placing ordinary bets, and in the UK gambling winnings are not taxed. Rules differ elsewhere — in many countries betting winnings are taxable — and bookmakers can restrict accounts that only take offers.
Why do I lose money on qualifying bets?
Lay odds are almost always a bit higher than back odds and the exchange takes commission on lay winnings. Choosing close back and lay odds keeps the qualifying loss small.
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For information and entertainment only — not betting advice. Gambling carries a real risk of loss, odds and settlement rules vary by bookmaker and country, and betting is only for adults where it is legal. Never stake more than you can afford to lose; if gambling stops being fun, get free, confidential help (for example 1-800-GAMBLER in the US, GamCare or BeGambleAware in the UK, or your local helpline).