About the Container Loading Calculator
This container loading calculator works out how many identical cartons fit inside a standard shipping container. Choose a 20-foot, 40-foot, 40-foot high-cube or 45-foot high-cube box, enter the carton length, width, height and gross weight, and it tests every allowed orientation to find the best uniform stacking pattern — then checks the result against the container’s maximum payload so you know whether space or weight runs out first.
It is meant for importers, exporters, freight forwarders and e-commerce sellers planning a full container load (FCL), comparing the cost per unit of a 20’ versus a 40’ box, or deciding whether a carton redesign would squeeze in another layer. Results include the cartons per row, column and layer, the cubic metres used and the volume and weight utilization percentages.
Container dimensions are typical internal figures for ISO dry containers; individual boxes and carriers vary by a few centimetres and payloads differ by tare weight. The calculation assumes one orientation for every carton, no pallets and no allowance for door clearance, carton bulge or dunnage, so the practical count is usually somewhat lower (mixed-orientation loading can occasionally add a few). Road weight limits in your country may also be lower than the container’s rated payload.
With the default inputs, the cartons per container is 600. Change any value above to recalculate instantly.
How to use the container loading calculator
- 1Choose the container type you are quoting.
- 2Pick metric or imperial units.
- 3Enter the carton’s outer length, width and height and its packed gross weight.
- 4Leave “this side up” on for fragile or oriented goods; turn it off to test laying cartons on their side.
- 5Read the cartons per container, the limiting factor and the comparison table for other container sizes.
Formula and method
For each allowed orientation of the carton, the calculator counts how many whole cartons fit along the container length, width and height (rounding down) and multiplies the three counts. With “this side up” on, only the two orientations that keep the carton height vertical are tried; with it off, all six are tested. The best orientation gives the space-limited count.
The weight-limited count divides the container’s typical maximum payload by the carton gross weight. The final answer is the smaller of the two. Volume utilization is the loaded cubic metres divided by the container’s internal volume. Uniform single-orientation stacking is a conservative, easy-to-load plan; specialist load-planning software can sometimes add cartons by mixing orientations.
- L, W, H
- Container internal length, width, height
- l, w, h
- Carton dimensions in the tested orientation
- ⌊ ⌋
- Round down to a whole number of cartons
Worked examples
60 × 40 × 40 cm cartons in a 40' high cube
Lengthwise, 12.032 m holds 20 cartons of 60 cm, the 2.352 m width holds 5 of 40 cm and the 2.698 m height holds 6 layers of 40 cm: 600 cartons, 57.6 m³ of cargo, or about 75% of the container volume. At 18 kg each the load weighs 10,800 kg, far below the payload, so space is the limit.
Heavy 25 kg cartons in a 20' container
Turning the 40 × 30 cm footprint so the 30 cm side runs along the length gives 19 × 5 × 9 = 855, but the original orientation gives 14 × 7 × 9 = 882, so that wins. At 25 kg each, 882 cartons weigh 22,050 kg — under the 28,200 kg payload, so space still limits.
Very heavy cartons where weight limits the load
A 40' standard container fits 24 × 5 × 7 = 840 cartons of 50 × 40 × 30 cm by space, but 840 × 35 kg would be 29,400 kg. Dividing the 26,700 kg payload by 35 kg allows only 762 cartons (26,670 kg), so weight is the limit and about 9% of the space stays empty.
Frequently asked questions
How many cubic metres (CBM) fit in a 20ft and 40ft container?+
A 20' standard container has about 33 m³ of internal volume, a 40' standard about 67–68 m³ and a 40' high cube about 76 m³. Usable loaded volume is typically 25–28 m³, 55–58 m³ and 65–68 m³ respectively once gaps and dunnage are allowed for.
What is the difference between a 40ft and a 40ft high cube?+
A high cube has the same length and width but is one foot (about 30 cm) taller: roughly 2.70 m internal height instead of 2.39 m. That extra height often allows one more layer of cartons, adding around 13% more volume for a similar freight rate.
How much weight can a container carry?+
Rated payloads are typically around 28,000 kg for a 20' and 26,500–26,700 kg for a 40' standard or high cube, depending on tare weight. Road limits are often lower — in the US a 40' container on a standard chassis is commonly limited to about 44,000 lb (20 t) of cargo — so check local rules.
Should I use a 20ft or 40ft container?+
Dense, heavy cargo such as tiles, metal or liquids often hits the weight limit before filling a 20', so a 40' adds cost without adding capacity. Light, bulky cargo fills space first and is usually cheaper per unit in a 40' or 40' high cube.
Why does real loading come out lower than the calculator?+
The calculation assumes perfectly rigid cartons, exact dimensions and no space lost to door clearance, corrugation bulge, pallets, airbags or securing. Allow a margin below the theoretical count; palletized loads lose more because pallet footprints rarely divide the container width evenly.