Discount impact calculator.
Enter price, cost, and your discount %. See your new margin and exactly how many MORE units you have to sell to recover the lost profit.
Your numbers
Per item. Defaults assume a €40 retail item with €18 COGS and a 20% off promo.
New margin per unit
A 20% discount doesn't cost 20% — it often costs 40%+ of your profit.
Discounts feel small because they're framed as a percentage of price. But your profit is the price minus the cost — and the cost doesn't budge. The discount comes out of your margin, not your revenue. On a €40 item with €18 cost, a 20% discount cuts margin from €22 to €14. That's a 36% margin hit for a 20% headline discount.
The formula
New margin = (price × (1 − discount %)) − costExtra units to match = (old margin ÷ new margin) − 1
The "extra units" reality check
This is the number to put in front of your team before any promo. If you have to sell 50% more units to make the same profit, you'd better have demand-elasticity data showing the promo will actually triple traffic. Most promos don't — they pull forward sales you'd have made anyway, often from your highest-margin customers.
When discounts make sense
Clearing seasonal stock you'd otherwise write off. Acquiring a customer whose lifetime value clearly exceeds the discount cost. New product introduction. Bundle to move slow-moving inventory. Not: a regular routine, a brand-positioning lever, or "to compete on price" without a margin advantage somewhere else.