Bundle Pricing Calculator

Written out

A bundle price sits below the sum of its parts, and the discount is the sum less the bundle price. What decides whether it works is the share of bundle buyers who would otherwise have bought only one item.

Written out: bundle contribution = bundle price − combined cost. Compare that against the contribution from the item they would have bought alone. If the bundle wins, it works on every incremental attachment and loses on every customer who was buying both anyway.

In practice

Item A at $42 with $18 cost; item B at $26 with $9 cost. Sold separately the combined price is $68 and combined contribution is $41. A bundle at $59 has contribution of $32.

Against selling A alone at $42 with $24 of contribution, the bundle earns $8 more. So every customer who takes the bundle instead of A alone is worth $8 more.

But every customer who would have bought both separately and takes the bundle instead costs $9. If 25% of bundle buyers fall into that group, the blended result is 0.75 × $8 − 0.25 × $9 = $3.75 per bundle, still positive, and less than half what the headline comparison suggested.

The limitations

The cannibalisation share is the whole calculation and it is rarely measured. Businesses assume most bundle buyers are incremental and the data usually says otherwise, particularly where the two items were already frequently bought together.

A bundle can also depress the perceived value of the individual items. Once a customer has seen A and B together for $59, paying $42 for A alone feels poor, and the anchor persists after the bundle ends.

Putting it to use

Bundle items that are rarely bought together rather than items that already sell as a pair. The first creates attachment; the second discounts a basket you already had.

Measure it by pulling the order history for the two items before the bundle launched. The share of orders containing both is a direct estimate of the cannibalisation rate, and it is available in five minutes.

Pure, mixed and leader bundling

Pure bundling sells the items only as a set. It maximises the bundle's perceived coherence and removes the choice, which suits products that genuinely belong together and fails badly where they do not.

Mixed bundling, offering the bundle and the components separately; is the usual ecommerce approach because it captures both the bundle buyer and the single-item buyer. The cost is the cannibalisation described above.

Leader bundling attaches a low-cost high-perceived-value item to a main product, which is closer to a gift with purchase than to a discount. Because the attached item costs you cost of goods and reads as retail value, this is usually the cheapest of the three to run and the one that damages the price architecture least.

One measurement worth running: compare the average order value of customers who took the bundle against those who bought the lead item alone in the same period. If the bundle buyers are not materially higher, the bundle is discounting baskets rather than building them.

That comparison is more informative than bundle conversion rate, which rises whenever the discount deepens and says nothing about whether the discount paid for itself.