Work out promotion lift instantly with clear inputs, formula shown and shareable results.
Promotional lift only pays if it exceeds the break-even lift implied by the margin given away. A 20% discount on a 38% margin needs roughly 34% more units just to hold gross profit flat, which is the test most promotion reviews skip.
Sales lift
Lift % = (Promotional units - Baseline units) / Baseline units x 100
Break-even lift
Required lift % = (Normal margin / Promotional margin - 1) x 100
The average of comparable non-promoted weeks, adjusted for seasonality. Using the immediately preceding week usually understates the baseline.
Yes. Customers stockpiling during the promotion depress post-promotion sales, so lift should be measured over a window that includes the dip.