You're probably shipping empty space

Here's something that doesn't get talked about enough in importing circles: most people are paying full price for containers they're only two-thirds filling.

A 40ft container costs the same whether it's packed to the ceiling or half empty. And when you're paying $2,800-3,500 for that box, leaving 30% of it unused means your per-unit freight cost is nearly 50% higher than it needs to be.

I've lost count of the number of times I've seen someone complain about "expensive freight" when the real problem was terrible packing.

Quick primer on container sizes

You've got three main options:

20ft Standard (20GP) — About 33 cubic metres, max ~21,700 kg. Great for heavy, dense stuff. Metal parts, ceramics, anything that weighs a lot relative to its size.

40ft Standard (40GP) — Around 67 cubic metres, max ~26,500 kg. The workhorse. Good for most general cargo.

40ft High Cube (40HC) — About 76 cubic metres, same weight limit as the 40GP. That extra foot of height makes a real difference for lightweight, bulky products — think furniture, large plastic items, textiles.

Here's the thing most people miss: your product hits one of two limits first. Either you fill the space (cube out) or you hit the weight limit (weigh out). A container of pillows will cube out long before it weighs out. A container of ceramic tiles will weigh out while it's still half empty by volume.

Knowing which limit you'll hit first is step one of packing efficiently.

How to measure what you're actually doing

Two numbers matter:

Volume utilisation = total cargo volume ÷ container internal volume × 100

Weight utilisation = total cargo weight ÷ container payload limit × 100

Whichever one hits 100% first is your constraint. And ideally, you want both as high as possible.

If your volume utilisation is 90% but weight utilisation is only 40%, you've got capacity to add heavier products. If your weight is at 95% but volume is at 60%, you're paying for a lot of air around a heavy load.

Things that actually help

Consolidate orders across products. This is the big one. Don't send three half-empty containers when you could send two full ones. If you're importing multiple SKUs from the same region, combine them. You save an entire container's worth of freight.

Fix your carton dimensions. I know this sounds nitpicky, but it matters more than you'd think. The internal width of a standard container is about 2.35 metres. Cartons that are 58cm wide fit four across perfectly (232cm total, tight fit). Make those cartons 50cm instead, and suddenly you've got 35cm of dead space per row. Across hundreds of cartons, that waste adds up fast.

Talk to your supplier about this. Good factories are happy to adjust packaging dimensions if you give them a reason.

Mix heavy and light products. If you import both dense and lightweight items, you can sometimes get them into the same container. The heavy stuff keeps you within volume, the light stuff uses the remaining weight capacity. Both product lines benefit from lower per-unit freight.

Get a loading plan. Before anything gets packed, either create or request a diagram showing exactly how the cartons should stack. Left to their own devices, factory workers will load things however is fastest — which usually means wasted space.

Know when LCL makes sense. If you can't fill a container, Less than Container Load (LCL) shipping lets you share space with other shippers. The per-CBM rate is higher, but you only pay for what you use. As a rough guide, LCL usually makes more sense below about 15 cubic metres. Above that, you're generally better off with a full container even if there's some empty space.

Let me put some numbers on this

Two scenarios, same container, same product:

Scenario A — 60% utilisation: Container: $3,200 / 2,400 units = $1.33 per unit in freight

Scenario B — 90% utilisation: Container: $3,200 / 3,600 units = $0.89 per unit in freight

That's $0.44 per unit saved. Sounds small. But ship 50,000 units a year, and you've just saved $22,000 — without negotiating a lower freight rate, without changing your shipping line, without doing anything except packing the box better.

Track it, improve it

The only way to get better at this is to actually measure it. For every shipment, note down:

• Container size used
• Total CBM loaded
• Total weight loaded
• Percentage of each limit used

After a few shipments, patterns emerge. Certain products consistently under-fill. Certain suppliers pack badly. Certain product combinations work together beautifully. That data turns container loading from an afterthought into one of your best cost-saving tools.