What are the internal dimensions of a container?

A 20ft GP is about 589 by 235 by 239 cm, a 40ft GP about 1203 by 235 by 239 cm, and a 40ft High Cube about 1203 by 235 by 269 cm. Payload limits are roughly 28 tonnes for a 20ft and 26 to 27 tonnes for a 40ft.

How are cartons fitted?

For cartons the tool tries all six rotations and picks the orientation that fits the most units in a simple grid, flooring the count in each axis. Pallets are kept upright and only their footprint is rotated.

Why does my load cube out before it weighs out?

Most general cargo fills the volume before reaching the weight limit, which the tool shows by reporting the smaller of the volume fit and the payload fit. Dense goods like tiles or liquids weigh out first instead.

A TEU is a twenty-foot equivalent unit, the standard way to count container capacity. A 20ft box is one TEU and a 40ft box is two TEU, which is why ocean carriers quote ship capacity in TEU.

Is this an exact load plan?

No. It is an idealised single-orientation grid with no mixed stacking, bracing, or dunnage. Real container fills typically run a few percent below the geometric maximum, so plan with some slack.

Container Load Planner (20ft/40ft/TEU)

Booking ocean freight starts with one question: how much fits in the box? This planner takes your carton or pallet size and the container’s true internal dimensions, then reports the unit count limited by both volume and payload, so you know whether your cargo cubes out or weighs out first.

How it works

The tool fills a simple 3D grid inside the container’s internal dimensions. For cartons it tries all six rotations; for pallets it keeps them upright and rotates only the footprint:

nx = floor(containerL / unitL)
ny = floor(containerW / unitW)
nz = floor(containerH / unitH)
fit by volume  = nx × ny × nz   (best orientation)
fit by payload = floor(payloadLimit / unitWeight)
units loaded   = min(fit by volume, fit by payload)

The smaller of the two is the real capacity, and the tool flags whether volume or weight is the binding limit.

Example and tips

Cartons of 40 by 30 by 30 cm at 8 kg each pack into a 40ft GP at roughly 2200 by volume, while the 26,680 kg payload allows about 3300 — so volume binds and you load 2200 cartons at around 80 percent volume utilisation. Switch to dense goods at 25 kg per carton and payload becomes the limit instead. Remember this is an idealised grid: leave a few percent of slack for bracing, dunnage, and the fact that real cartons rarely tessellate perfectly.