Packaging is evaluated as a material cost far more often than as a system cost, which is why so many "savings" projects reduce the carton price and increase the delivered cost per unit. The three layers interact, and freight is usually the largest term.

The three layers

  • Primary — in contact with the product: the bottle, sachet, pouch, film. Drives shelf life, consumer experience and most regulatory obligations.
  • Secondary — the shipper case, shrink bundle or display-ready unit. Drives handling cost, retail replenishment labour and shelf presence.
  • Tertiary — the pallet, slip sheet, stretch wrap and container plan. Drives freight cost, which is where the real money usually is.

Start from the container, not the carton

The correct evaluation order is backwards from how it is usually done. Fix the pallet footprint first, then the case dimensions that tile that footprint without overhang, then the primary pack that fills the case efficiently.

Cases per pallet     = (Pallet area / Case footprint) x Layers
Units per pallet     = Cases per pallet x Units per case
Freight cost per unit = Container cost / (Pallets per container x Units per pallet)

A worked example: a 40-foot container holds 20 standard pallets. If a case redesign lifts cases per pallet from 48 to 54 — an 12.5 per cent gain from eliminating 3 cm of overhang — freight per unit drops by the same 12.5 per cent. On a lane costing 3,200 per container carrying 11,520 units, that is a saving of about 0.031 per unit, permanently, on every shipment.

Cube versus weight

Know which one binds. Light bulky products (tissue, snacks, empty containers) cube out — the container fills before it reaches weight limit, so volume efficiency is everything. Dense products (liquids, canned goods) weigh out, and reducing packaging volume saves nothing on freight. Optimising cube on a weight-limited product is wasted engineering.

Case count and the retail trade-off

Case countRetailer viewSupply chain view
Large (24-48)Too much stock per facing, slow rotation in small outletsLower handling cost per unit, better cube
Medium (12-24)Workable for most tradeBalanced
Small (6-12)Preferred by small outlets, better freshnessMore cases to handle, worse cube, higher carton cost per unit

The correct case count depends on the dominant channel. A case size optimised for modern trade will sit unsold in general trade because the outlet cannot fund a full case.

Compliance is a design input, not a review step

Label content requirements — net quantity declaration, ingredient list, allergen emphasis, country of origin, manufacturer details, batch and date coding, recycling marks — consume physical area on the primary pack. Designing artwork first and discovering the mandatory panel does not fit is a common and expensive rework. Establish the mandatory area budget before the design brief goes out.

Date and batch coding also constrains the substrate and the line: a matte varnish that looks excellent may not accept a legible inkjet code at line speed.

Evaluating a proposed change properly

  1. Material cost per unit — the number everyone starts and usually stops at.
  2. Line efficiency effect — a thinner film that runs 6 per cent slower has erased its own saving.
  3. Damage rate change — measure in transit trial, not in the lab.
  4. Freight per unit — from the pallet pattern, as above.
  5. Retail handling and shelf impact — ask the trade before you commit.
  6. Compliance and artwork rework cost — one-off but real.

A packaging change that improves items 1 and 4 while degrading 2 and 3 is common, and the net is frequently negative. Insist on all six lines before approval.