Enter your bookmaker back stake and odds, the exchange lay odds and commission to calculate your lay stake, liability and both matched-betting outcomes. Choose Qualifying bet for a cash stake, Free bet: SNR when the promotional stake is not returned, or Free bet: stake returned (SR) when it is. Compare qualifying loss or calculated free-bet profit before placing your bets. The calculator is free, with no sign-up needed.
Check that your lay bet is fully matched and both bets use compatible settlement rules. Recheck changed odds before placing a bet.
Choose this when the bookmaker stake is your own money. The calculation includes that stake as a cost if the back bet loses.
Choose SNR when a winning free bet pays only the winnings, excluding the promotional stake. The free-bet token is not counted as your own cash outlay.
Choose SR only when the offer returns the promotional stake as part of a winning return. It produces a different lay stake from SNR. Check the promotion terms before choosing.
The calculator balances the bookmaker and exchange odds you enter. A small negative total in qualifying mode is the calculated cost of completing that qualifying bet. The loss depends on your stakes, odds and exchange commission; the calculator does not find the best qualifying opportunity.
These examples use decimal odds, no back commission and no advanced adjustments.
Back stake £10 · back odds 2.00 · lay odds 2.10 · exchange commission 2%.
Lay stake
£9.62
Liability
£10.58
Back wins
−£0.58
Lay wins
−£0.57
The calculated qualifying loss is about 57–58p. Penny rounding accounts for the difference between outcomes.
Stake not returned: free-bet value £20 · back odds 3.00 · lay odds 2.80 · exchange commission 2%.
Lay stake
£14.39
Liability
£25.90
Back wins
+£14.10
Lay wins
+£14.10
These inputs give approximately £14.10 calculated profit. A different set of odds or commission produces a different result.
Calculated outcomes assume the entered stakes and odds are matched and the bets settle as modelled. They do not determine offer eligibility or withdrawal rules.
Custom Stake lets you adjust the lay stake away from the standard balanced calculation. An underlay uses a lower lay stake and favours the back-win outcome; an overlay uses a higher lay stake and favours the lay-win outcome. Check both totals and the changed liability.
Use the Odds format selector for decimal, fractional or American odds. Advanced options contains extra adjustments such as back commission, Rule 4 and an odds boost; use them only when they apply to your bet.
It calculates the lay stake, exchange liability and net back-win and lay-win outcomes from the stake, odds, commission and bet type you enter.
It is the negative net outcome of a qualifying back-and-lay bet. Check both result totals to see the calculated cost before proceeding.
Use SNR when the promotional stake is excluded from a winning return. Use stake returned (SR) only when the offer includes it. Check the terms; selecting the wrong mode changes the lay stake and results.
It is the amount you can lose on the exchange if your lay bet loses. For decimal lay odds, liability is lay stake × (lay odds − 1). Check that your exchange balance covers it.
Stakes are rounded to amounts you can place, and the resulting figures are displayed to the nearest penny. That can leave a small difference between the two totals.
Update the unmatched lay odds and recalculate. If the back bet is already placed, keep its actual stake and odds. If some of the lay bet is already matched, account for that existing exposure before placing anything else.