Bundle Pricing & Discount Stack
Price a bundle and stack discounts — bundle price or %, coupons applied sequentially or additively, a voucher — with margin, effective discount and allocation.
The list total, the price after each step, the final price and effective discount, margin when unit costs are given, tax, and each item’s share of the final price by list price.
Example: Three items listing 368 sold as a 299 bundle, then 10 % and 5 % coupons and 10 off: 245.65 (33.2 % off); the two coupons stacked are 14.5 % off, not 15 %; margin 157.65 on 88 cost.
Discounts stack
by multiplication.
How the bundle price and the coupons combine, why 10 % + 5 % is 14.5 %, and how the price is allocated back to items.
The stack
A bundle price (or a bundle discount) sets the starting point; further discounts are applied either sequentially — each on the price left, price × (1 − d₁)(1 − d₂)…, which is what most tills and shops do — or additively, summed and applied once, price × (1 − Σd). Sequential 10 % and 5 % is 14.5 % off; additive is 15 %. A fixed amount off comes last and cannot go below zero.
Margin and allocation
With unit costs on the items the page shows the margin after the whole stack and flags a sale below cost or under 10 %. The final price is allocated back to the items in proportion to their list prices — the relative-price method used for revenue recognition and returns of one item from a bundle.
Not modelled
Demand, the perceived value of a bundle, price anchoring, rounding to .99, minimum-price laws and tax rules by item; tax here is one rate on the final price. Nothing leaves the browser; the same four anonymous usage counts as the rest of the site apply.
SOURCES
- Sequential stacking: price × Π(1 − dᵢ); additive: price × (1 − Σdᵢ); allocation of the bundle price to items in proportion to stand-alone (list) prices — the relative-price method
Last reviewed 21 September 2026. How results are checked: How we verify.