Container Loading for Mobility Aids: Carton Cube and Mixed-SKU Math

A landed-cost planning guide for US dealers and distributors · Updated 2026-10-23

Two suppliers can quote the same FOB unit price and still land thousands of dollars apart. The difference is usually not the product — it is the carton. Before you compare prices on any mobility aid line, compare the cube.

Why carton cube comes before price

Ocean freight under DDP is priced per container, not per unit. Whatever fits inside the box is what your freight, clearance and delivery get divided across. A model that ships flat and packs to 0.12 cubic metres puts roughly three times more units under the same freight cost as an assembled one packing to 0.36 cbm. Same product category, same factory gate — very different landed cost per unit.

This is why we ask for nothing more than a delivery address to quote DDP, but we will always ask which models you want: the carton dimensions of those models decide the container plan. Our DDP door-delivery guide explains how those numbers become a single fixed quote.

The cube formula

Carton cube in cubic metres is simple:

cbm = length (cm) × width (cm) × height (cm) ÷ 1,000,000

Illustrative example. A flat-packed commode chair master carton measuring 62 × 24 × 88 cm comes to 0.131 cbm. A 40-foot high-cube container with a practical fill of about 68 cbm holds roughly 510 units of that model loaded loose — before you account for stacking limits, irregular voids and dunnage. The exact figures for any UNIONCARE model are supplied with the quotation; the arithmetic is the part you should run yourself on every quote you receive.

What actually fits: practical container fill

Container brochures list internal volume, but nobody loads 100% of it. Cartons are not rectangles of water. Plan on practical fill:

Values vary by shipping line and container build; treat them as planning numbers and confirm payload with your forwarder.

Cube-bound or weight-bound: know which one you are

Aluminium walkers, rollators, shower chairs and crutches are almost always cube-bound: the container fills up long before it approaches the weight limit. Heavy steel bariatric commodes are the exception — a full load of those can hit the payload ceiling before the cube runs out, especially once you consider that on US inland legs, road weight rules often cap the cargo in a container well below the ocean payload (frequently around 19–20 tonnes depending on equipment and state).

The practical consequence: for aluminium lines, negotiate on volume and loading efficiency. For steel bariatric lines, also check gross weight per container and your drayage leg.

Flat-pack beats assembled, every time

Most of our aluminium and steel frames ship knock-down: legs off, or folded flat, with retail-ready cartons sized to the collapsed footprint. Buyers sometimes worry knock-down means harder assembly for their customers — it does not, because the retail carton includes tools and instructions, and end users assemble once.

• Assembled packing can triple the cube of a folding frame. You pay freight on air.
• Knock-down / fold-flat packing is how a 40HQ absorbs 500+ commode chairs or walkers instead of fewer than 200.
• If a competitor's quote looks dramatically cheaper per unit, check whether their carton is simply bigger — and whose freight bill absorbs the difference.

Pallets or loose loading?

If your 3PL charges per hour to hand-unload a loose container, pallets may still win on total cost. Tell us how the container will be received and we plan the loading accordingly.

Mixed-SKU containers: how the math really works

Dealers rarely want 500 of one model. The realistic first order is a spread: commodes, shower chairs, toilet rails and a couple of walker lines, each in modest depth. That is exactly what a mixed container is for.

• Minimums are per SKU, not per container. Our MOQ is 50 units per SKU, with no separate per-container minimum.
• Plan by cube, not by gut. Add each line's carton cube × quantity; aim to land within a few cbm of practical fill. A short container wastes freight; an over-declared one forces last-minute line cuts.
• Heavy goes low, light goes high. Steel bariatric models load on the container floor; crutches, canes and boxed seat cushions cube out the top rows. This is planned before the container is stuffed, not improvised at the factory.
• Mixed private label works too. Cartons, manuals and labels switch per SKU; the loading plan just gets one more column. See how the private label programme works.

The six numbers to ask any supplier

1. Master carton dimensions (cm) per model
2. Gross weight per carton, and cartons per master pack
3. Knock-down or assembled packing
4. Palletizable or floor-load only
5. Units per 20GP and per 40HQ at practical fill
6. Stackability limits (crush strength matters for cube-out rows)

A supplier who produces these instantly ships from a factory they control. One who goes quiet for two days is asking someone else. For more vetting questions, see Factory or Trader? and, for the same discipline applied to one product line, Bulk Commode Chairs Wholesale.

From carton cube to a DDP quote

When you send us your model list and destination, we do this math as step one: pick the container size, plan the mixed-SKU load, then price freight, clearance, duty and final-mile on that plan. That is why our DDP landed cost is a single number, quoted before you commit, and it does not move afterwards — 5–6 weeks door to door.

Send Your Model List for a DDP Quote