Container Loading Calculator

Estimate how many items or boxes fit inside a 20ft or 40ft shipping container from item dimensions, with optional weight limit check.

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Container type

Internal: 590 × 235 × 239 cm

Item dimensions (cm)

Length

Width

Height

Item weight kg (optional)

Max payload kg (optional)

Enter item dimensions Fill in the item's length, width, and height to calculate how many fit in the container.

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Container loading calculator: how many units fit in a shipping container

A container loading calculator estimates how many boxes or items fit inside a standard 20ft or 40ft shipping container from item dimensions. It tries all six item orientations to maximise the theoretical count, then applies a practical packing efficiency factor of 85% to account for real-world loading constraints.

Standard container dimensions

ISO standard dry containers have closely specified internal dimensions. The 20ft standard container has an internal length of approximately 5.90 m, width 2.35 m, and height 2.39 m, giving a usable volume around 33 CBM. The 40ft standard container is roughly 12.03 × 2.35 × 2.39 m (67 CBM), and the 40ft high cube adds 30 cm of extra height (76 CBM).

Maximum gross weight for a standard 20ft container is approximately 28,200 kg payload; a 40ft can carry around 26,700 kg. The weight limit often becomes the binding constraint before the volume limit for dense goods.

Theoretical vs practical units

The theoretical maximum assumes items can be stacked perfectly from floor to ceiling with no gaps. In practice, loading efficiency is typically 80–90% due to item fragility, stacking constraints, load-securing requirements, and the difficulty of filling the last partial row.

This calculator applies an 85% efficiency factor to the theoretical maximum to produce the practical estimate. For items with specific stacking restrictions, adjust your expectations accordingly.

Theoretical units = ⌊C_L / I_L⌋ × ⌊C_W / I_W⌋ × ⌊C_H / I_H⌋

C = container dimension, I = item dimension. All six orientations are tested; the best is used.

Practical units = ⌊Theoretical units × 0.85⌋

85% packing efficiency applied to account for real-world constraints.

Frequently asked questions

Which container type should I choose?

A 20ft container is better for heavy, dense goods because it typically has a higher weight-to-volume ratio limit. A 40ft or 40ft high cube is more efficient for light, bulky goods where you will fill the volume before hitting the weight limit. The high cube is useful for tall pallets or items.

Why is the practical estimate lower than the theoretical maximum?

Real loading involves irregular item sizes, fragile goods that cannot be stacked, load-securing bracing, and human error in placement. The 85% factor is a common industry rule of thumb. For purpose-built items loaded by machine, efficiency can reach 95%; for irregular or fragile goods it may be 70% or lower.

Does this account for pallets?

No — the calculator treats items as directly stacked in the container. If goods will be palletised first, use the pallet calculator to find how many items fit per pallet, then calculate how many pallets fit in the container using the pallet footprint and pallet+load height as the item dimensions.

Container Loading Calculator

Container loading calculator: how many units fit in a shipping container

Standard container dimensions

Theoretical vs practical units

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