Free Coupon Profit Impact calculator with clear step-by-step results.
A coupon costs full margin on every order that redeems it, including the ones that would have converted anyway. Blending redeemed and unredeemed orders gives true profit per order, and the break-even lift is the volume increase the promotion must generate before it stops destroying profit.
Blended profit
Profit = base profit x (1 - redemption) + discounted profit x redemption
Break-even lift
Lift % = (base profit - blended profit) / blended profit x 100
Both matter, but redemption decides how much of your existing demand you discount for free. A deep coupon redeemed by 5% of orders can cost less than a shallow one redeemed by 60%.
Site-wide coupons often produce a lift in the single digits while cannibalising heavily. Compare the break-even figure against measured incrementality rather than total coupon orders.