Container Loading Calculator

cartons by volume = the largest of floor(L ÷ l) × floor(W ÷ w) × floor(H ÷ h) over all six orientations, and cartons by weight = floor(payload ÷ weight per carton)

L, W, H

The container's internal length, width and height in cm

l, w, h

One carton's dimensions in cm, reassigned to the container axes for each of the six orientations

payload

The container's maximum cargo weight in kg — the gross limit minus the tare weight of the box itself

weight per carton

The gross weight of one carton, packaging included

Use it to size a shipment before you book: it tells you whether a consignment needs one container or two, and whether the constraint is space or mass. That second question matters because the two failure modes look nothing alike — a light cargo that fills the box wastes volume, a dense cargo that hits the weight limit leaves the top half of the container empty, and the freight is priced the same either way. It is also the quickest way to test whether a carton should be redesigned: a few centimetres off one side often changes how many fit per layer, and that change can be large. It cannot tell you the freight cost, which depends on the trade lane, the commodity and the Incoterm rather than on how full the box is.

1. 60 × 40 × 40 cm cartons at 12 kg in a 40 ft standard container

   1. Best orientation: 1203.2 ÷ 60 = 20 along the length, 235.2 ÷ 40 = 5 across the width, 239.3 ÷ 40 = 5 up the height
   2. Cartons by volume: 20 × 5 × 5 = 500
   3. Cartons by weight: 28,870 ÷ 12 = 2405, so weight is not the limit here
   4. Answer: 500 cartons, weighing 6,000 kg and occupying 48.0 m³ of the 67.7 m³ internal volume — 70.9% full

   Volume is the binding constraint, and it binds hard: 500 cartons at 12 kg is under a quarter of the payload. The remaining 29% of the container is not space you can recover by packing better — it is the gap left by rectangular cartons in a rectangular box, and it is why real stuffing figures rarely beat this one.

2. 40 × 30 × 30 cm cartons at 45 kg in a 20 ft container

   1. Best orientation: 589.8 ÷ 40 = 14 along the length, 235.2 ÷ 30 = 7 across, 239.3 ÷ 30 = 7 up
   2. Cartons by volume: 14 × 7 × 7 = 686
   3. Cartons by weight: 28,300 ÷ 45 = 628, which is the smaller of the two
   4. Answer: 628 cartons, weighing 28,260 kg

   This is the case that makes the two limits worth showing separately. Space would take 686 cartons, but the container runs out of payload first, so 58 cartons' worth of volume is unused — and 28,260 kg is close enough to the limit that the last carton is decided by the CSC plate rather than by arithmetic.

Every carton count here is an upper bound computed from a rectangular packing model: cartons are perfect cuboids, they sit flush against each other and against the walls, and they stack to the full internal height. Real stuffing is done by hand or by forklift and reaches 80 to 85% of internal volume in the best case, usually less, because pallets leave gaps underneath, mixed consignments break up the neat blocks, and cartons cannot always be stacked to the roof without crushing the bottom layer. The door opening is also shorter than the internal height on every standard container — on a 40 ft high cube the door is around 2585 mm against an internal height of 2698 mm — so the last few centimetres of height are not usable in practice. The internal dimensions are one carrier's published figures rather than a standard: ISO 668, and the GB/T 1413 that adopts it, fixes external dimensions and ratings — and minimum internal dimensions for some types — while the full internal dimensions for a given type sit in the ISO 1496 series. Carriers differ from each other by a centimetre or two. The payloads are typical figures for the box type, not values for the box you will get: tare weight varies with age and construction, and the maximum gross weight of a 40 ft container has more than one published value in circulation. The number that binds is the one on the CSC safety approval plate on the door of the actual container. Finally, this page ignores dangerous goods segregation, weight distribution along the floor, and the axle limits of the truck and the stack weight limits of the ship, all of which can cut the usable payload below what the plate says.

How many cartons fit in a 40 ft container?

It depends entirely on the carton, because the count scales with the cube of its size: halve every side and eight times as many fit. As a worked example, 60 × 40 × 40 cm cartons fit 500 to a 40 ft standard container by volume, occupying 48 m³ of the 67.7 m³ internal volume. Change the carton to 50 × 35 × 30 cm and the same container takes 1,008. Enter your own dimensions above rather than scaling from someone else's figure — the orientation the cartons end up in matters as much as their size.

Why is the count lower than the container volume suggests?

Because a container is 67.7 m³ and 500 cartons of 0.096 m³ each is only 48 m³. The rest is the space a rectangular packing cannot reach: the strip left over when the carton width does not divide the container width evenly, the same along the length, and whatever is left under the roof. The utilization figure on the results panel is your cartons' total volume divided by the container's internal volume, and the example above comes to 70.9% — which is a good result for a model that assumes perfect packing, since real stuffing is generally lower.

What is the difference between a 40 ft standard and a 40 ft high cube?

Only the height, and therefore only the volume. Both are 1203.2 cm long and 235.2 cm wide internally, but the standard box is 239.3 cm high and the high cube is 269.8 cm, so the high cube carries 76.4 m³ against 67.7 m³ — about 13% more. The tare weight is slightly higher, so the payload is slightly lower, and the door opening is a little taller but still shorter than the internal height. For light, bulky cargo the high cube is usually the better box; for dense cargo the extra height is wasted and the lower payload hurts.

What happens if the cargo is heavier than the payload?

The page reports the weight-limited count as the answer and shows the volume-limited count beside it, so you can see how much space goes unused. In the 20 ft example on this page, 40 × 30 × 30 cm cartons at 45 kg fill the container at 628 cartons — 28,260 kg — while the space would have taken 686. The remaining volume cannot be used, and the only ways to recover it are to load a lighter cargo in the same box or to split the consignment across two containers. Note that the payload shown is typical for the box type; the figure that binds is on the CSC plate of the container you are actually given.

Does the door opening matter?

It matters more than most people expect. The door opening is shorter than the internal height on every standard container, so the top few centimetres cannot be loaded even though they count in the volume — on a 40 ft high cube the door is around 2585 mm against an internal height of 2698 mm. The door is also narrower than the internal width. This page uses the internal dimensions throughout, which is why its count is an upper bound rather than a loading plan; if your cartons are close to the door height, check against the door dimensions before you commit.

• Intermodal container — standard sizes, internal dimensions and the ISO 668 / ISO 1496-1 split — Wikipedia
• Twenty-foot equivalent unit — how container capacity is counted and why the 20 ft box is the unit — Wikipedia