Work one real sum before anything gets booked: four hundred cartons of an 8-litre camera feeder at roughly 0.07 CBM each add up to about 28 cubic metres, while a 20ft container gives back only about 24-26 usable CBM once actual loading takes its share. That order needs a bigger box than instinct suggests — and the discovery costs nothing in a spreadsheet, plenty at the terminal.
From carton to cube: the three multiplications
Freight is invoiced by the cubic metre while buyers think in units; that mismatch is where load plans go wrong. CBM — cubic metres — is the unit vessels are priced in, and every order converts the same way. Take the outer master carton — never the retail box hiding inside it, since shoppers meet one and vessels carry the other. Measure its length, width and height in metres, multiply the three for the volume of one carton, then multiply again by the carton count. Hold the total against a realistic capacity, not a brochure one: a hundred cartons at 0.07 CBM fill about 7 cubic metres, and four hundred already demand 28.
Dimensions deserve two safeguards. Collect them in writing, then measure the pre-shipment sample yourself, because cartons change between runs — a foam insert can quietly add a couple of centimetres to every side. Far better to learn that while the quote is still negotiable than after it hardens.
Stated volume against the space you can really fill
The figures printed in brochures assume perfect loading; pallet footprints, door clearance and stacking discipline all take space back in reality. Plan on the lower band, treat the numbers as rules of thumb, and confirm for every load:
| Box type | Nominal cube | Planning band at 85-92% filling | Where the difference goes |
|---|---|---|---|
| 20GP | ~28 CBM | ~24-26 CBM | Pallet footprints, door swing, stack rules |
| 40GP | ~58 CBM | ~49-53 CBM | The same losses, spread across a longer floor |
| 40HQ | ~68 CBM | ~58-63 CBM | Extra height helps, though stacking limits still bite |
Cube is only half of the constraint; weight is the other half. Dense cargo reaches the weight limit while air remains; airy cargo fills the cube long before the scale notices. Both figures belong in your planning from the first quotation.
Loose cartons or pallets: what the cube buys back
Palletising is a trade rather than an upgrade. On the cost side, a palletised load surrenders roughly 10-15% of the usable cube. On the return side: forklift unloading instead of hand work, fewer crush claims, and quicker deconsolidation on the way to regional distribution centres.
| Decision factor | Loose floor load | Palletised load |
|---|---|---|
| Volume surrendered | None | Roughly 10-15% of the cube |
| Unloading at destination | By hand, slower | By forklift, faster |
| Crush exposure | Rides on stack discipline | Lower, inside stack limits |
| Pays off when | Your warehouse has staff and time | Freight continues on to regional DCs |
Stack behaviour deserves a question of its own: a master carton of the 32oz 3-in-1 stainless travel bottle in printed retail boxes stacks nothing like a carton of rugged feeders, and at six layers high the difference decides. The printed box is the weak link in the chain, and a dented corner is a return nobody ordered. The rule is blunt — spend money on cube only when the labour savings at the destination are real, and put the question to the team that will actually lift the cartons, not only to the forwarder who prices the movement.
The loading facts to lock down before booking space
A freight rate quoted without a loading configuration is a figure waiting for facts. The best-structured enquiry ever to reach our export desk came from a buyer in Ireland: datasheets, dimensions, weights, then the carton, pallet and container configuration, and only after that EXW and FOB pricing — the configuration fixes landed cost long before any rate does. Three lines make an enquiry complete:
- Per carton: quantity, outer dimensions in metres, gross weight.
- Per pallet: count, footprint, and the stacking pattern planned.
- Per container: the box you intend to book and the filling efficiency assumed.
A supplier who attaches those lines to a quotation is telling you something about how the rest of the order will run. And confirm certifications per SKU and per market — CE, FCC or RoHS where they apply — instead of assuming one blanket approval covers the whole container.
Why a first order usually shares a box
A mixed-SKU load asks for a map before capacity: the heavy cartons go low, the light ones high, and anything carrying liquid sits far from electronics. Camera feeders and cartons with liquid risk should never share a box, and weight distribution matters for the VGM reason below. For a first order, the larger question is whether to fill a box at all. Wholesale minimums can sit near 50 units for small programmes and own-brand trials, which lets one mixed LCL shipment answer the demand question at a fraction of a container's outlay — and a paid sample, covered in our factory sample testing guide, clears most quality doubts before even that. Meanwhile a dedicated 20GP full of unproven stock parks cash and warehouse space for months. Check destination electrical standards against the plug, voltage and wattage guide before the SKU mix is locked.
Most accounts grow along the same line: LCL while learning, a shared 40GP when monthly volume passes a few pallets, then a dedicated 40HQ for the repeat winners. Own-brand at volume rewrites the arithmetic once more — OEM production begins at 1,000 units over 15-25 days — so from that point container planning becomes a standing routine rather than a one-off. The small-order pricing ladder and the branding tier cost comparison cover what those commitments cost per unit.
Port paperwork that delays vessels: get these three settled early
Verified gross mass is a legal gate at the port — miss the weigh-in and a vessel slot slips — so settle contractually who provides the verified figure. A manufacturing partner should pass the forwarder real carton weights plus a pallet map, never estimates. Then negotiate free time at destination, because demurrage accrues daily, and request a preview of destination charges before the vessel sails — the landed-cost sheet should never be where surprises surface. The forwarder owns the timetable; the numbers remain the buyer's job.
Cube questions our packing line fields daily
What carton count is realistic for a 20-foot box?
Divide usable volume by carton volume, remembering that both numbers move. At 85% filling a 20GP leaves roughly 24 CBM to load; set against a 0.07 CBM carton, that is about 340 cartons on paper. Read the figure as a ceiling: door clearance and stacking rules will trim it further, and a feeder carton loads nothing like a compact bottle carton. Confirm per SKU.
Shared container or a whole box for the first shipment?
LCL, in most cases. Wholesale minimums rarely approach a container's worth, and locking a trial 20GP of unproven stock parks cash for a quarter while you are still learning the all-in cost of a mixed load. Move to a shared 40GP once repeat orders earn it, and keep the dedicated 40HQ for the winners your shelf data has confirmed.
Does palletising cost money or save it?
Palletising spends cube to buy handling speed; loose loading protects the carton count and spends labour instead. Let the conditions at the receiving dock make the call, not the headline rate.
Send us your quantities and destination port, and expect the reply to carry carton data and a loading plan alongside the rate — not enthusiasm in place of them.
