Bundle Pricing Calculator — Combine + Discount Math

Cannibalisation decides whether a bundle makes money

The arithmetic is the easy part. Three products at $99, $149 and $79 total $327; a 20% bundle discount is $65.40 off, giving a bundle price of $261.60. That is correct and the calculator will always get it right.

What it cannot tell you is whether that bundle earns anything, because a bundle only creates value if it changes behaviour. Split the buyers:

• Someone who would have bought one item and now buys the bundle. Genuine incremental revenue — the bundle worked.
• Someone who would have bought everything anyway and now pays $261.60 instead of $327. Pure margin lost, no behaviour changed at all.

The second group is cannibalisation, and it is invisible to any calculator because it depends on what those customers would have done otherwise — a counterfactual, not a number you can look up. A bundle can show a sensible discount and a plausible price while losing money overall, simply because the second group outnumbers the first.

Why bundles work when they work

The mechanism is worth understanding, because it tells you which bundles to build. Different customers value the same items differently: one person values A highly and B little, another the reverse.

A bundle priced below the sum captures both, because each pays less than their own valuation of their preferred item and more than their valuation of the other. Their willingness to pay for the pair is similar even though their reasons are opposite.

Which gives the condition precisely: this only works when valuations vary in opposite directions across customers. Bundling two items that the same people value equally highly achieves nothing at all except a discount.

The design rule that follows

Bundle complements and items with genuinely varied appeal — not your two bestsellers.

Bundling the two most popular products is the classic error, and now the reason for it is clear rather than a matter of taste: the people attracted by that bundle are overwhelmingly the ones who would have bought both regardless. You have handed a discount to your best customers and changed nobody's behaviour.

Cost of goods matters too

A bundle of digital goods costs nothing extra to deliver, so almost any incremental sale is worth having. A bundle of physical goods carries real cost per unit, so the discount comes out of a genuinely smaller pot and the cannibalisation hurts proportionally more.

For the margin arithmetic — how much profit a given discount actually consumes — see the discount percentage calculator.

What the tool does not model

Cannibalisation rate, cost of goods, and take-up. It sizes the offer; it does not tell you whether to make it. Add as many items as you like — the tool keeps at least one — set your discount, and it returns the total, the saving and the bundle price. The judgement is yours, and this is general business information rather than financial advice.