Bulk Pricing Calculator

The arithmetic

Bulk pricing sets a lower unit price at higher quantities. The arithmetic is simple; the judgement is whether the discount is funded by a genuine cost saving or is simply a lower price.

The genuine savings are real and calculable: one order costs one pick, one pack, one label and one payment fee regardless of how many units are in it. A ten-unit order saves nine sets of those fixed costs against ten separate orders.

The same thing with real figures

A $58 product with $26.10 of goods and $6.40 of per-order fulfilment and payment cost. A single unit contributes $25.50.

Ten units in one order: revenue at a 12% bulk discount is $510.40, goods are $261, fulfilment is $6.40 for the whole order. Contribution is $243, $24.30 a unit, against $25.50 at full price.

So a 12% discount costs only $1.20 a unit because the fulfilment saving funds most of it. Against ten separate full-price orders the contribution would be $255, so the bulk order gives up $12 in exchange for nine fewer orders to process.

The catch

The fulfilment saving is not linear. Ten units in one box saves nine picks; ten units that need two boxes saves less, and ten heavy units may cost more to ship as one consignment than the per-unit rate suggests.

It also assumes the bulk buyer would otherwise have bought ten units at full price. Frequently they would have bought three, and the discount has bought seven incremental units rather than discounted ten existing ones, which is a much better trade than the arithmetic above shows.

Applying it

Set the discount at or below the fulfilment saving where possible, so the bulk price costs nothing in contribution per unit. That is usually 8% to 15% depending on how large the per-order costs are relative to the item price.

Where you want to go deeper, do it knowingly and for a reason: clearing stock, winning a trade account, or displacing a competitor. A deep bulk discount offered by default to anyone who asks is a price cut with extra steps.

Where to set the quantity breaks

The break has to sit above the natural order size, or it discounts orders that were already happening. If the typical order is two units, a break at three creates a reason to add one; a break at two rewards behaviour you already had.

The way to find it is the order size distribution rather than the average. A catalogue where most orders are one unit and a tail buys ten needs a different structure from one where everything clusters at three. The average tells you neither.

Two or three breaks is usually enough. More than that complicates the decision without adding much, and the top break should be reachable by your better customers rather than theoretical, a break nobody crosses is a rate card with extra rows.

Bulk pricing also has a stock consequence worth modelling. A break that moves five units at a time depletes stock five times faster, which shortens the reorder cycle and raises the chance of a stockout between deliveries.

For a product with a long lead time that can be expensive, the bulk discount produces the volume and the stockout that follows costs more than the discount saved. Safety stock has to be set against the order size distribution the discount creates, not the one that preceded it.