Container Load Calculator Widget
Give exporters and forwarders a container loading estimate. Users pick a 20', 40' or 40' high cube container and enter one box size and weight; the widget tries every way the box can be turned and reports how many fit, the grid, the volume used and whether the payload limit is reached first.
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<iframe src="https://a2z.tools/embed/w/container-load-calculator" title="Container Load Calculator by A2Z Tools" width="100%" height="780" style="border:0;width:100%" loading="lazy" allow="clipboard-write"></iframe>
A plain iframe. Works everywhere, including site builders that strip scripts. Adjust height if your content needs more room.
<div data-a2z-widget="container-load-calculator" data-height="780"></div> <script async src="https://a2z.tools/embed.js"></script>
Adds a small script (what it does) that sizes the widget to fit its content, loads it lazily and keeps it isolated from your page's CSS.
Works with
How it works
The container's inside length, width and height (Ocean Network Express reference values: 5,898 x 2,350 x 2,390 mm for a 20' dry, 12,032 x 2,350 x 2,390 mm for a 40' and 2,695 mm high for a 40' high cube) are divided by the box dimensions with whole-number rounding down. All six orientations of the box are tried - each of its three sides can point along the container, then either remaining side can stand up - and the orientation with the biggest count wins. Every box in the load is turned the same way, so this is a simple grid, not a mixed-orientation optimiser; switch on 'Keep boxes this way up' to allow only the two upright turns. The space count is then capped by the payload (28,330, 26,840 or 28,800 kg) divided by one box's weight. The widget also warns when the chosen orientation would not pass through the door opening of 2,340 mm by 2,280 mm (2,585 mm on a high cube).
Calculation method
- For each of the 6 orientations (a, b, c) of the box: n = floor(CL / a) x floor(CW / b) x floor(CH / c)
- Upright only: c = box height, a/b = length/width in either order (2 orientations)
- Boxes = min(best n, floor(max payload / box weight))
- Utilisation = boxes x box volume / container volume
- Inside (mm) and payload (kg): 20' 5,898 x 2,350 x 2,390, 28,330; 40' 12,032 x 2,350 x 2,390, 26,840; 40' HC 12,032 x 2,350 x 2,695, 28,800
Worked examples
Cartons in a 20' dry
Inputs: 50 x 40 x 30 cm, 15 kg, 20' dry, any orientation
Result: 392 boxes (14 x 4 x 7); 71% of volume; 5,880 kg
Limited by space.
Heavy boxes in a 40' dry
Inputs: 40 x 30 x 30 cm, 40 kg, 40' dry
Result: 671 boxes; 26,840 kg (payload limit); 35.7% of volume
1,470 would fit by space - the payload governs.
A single-orientation estimate for planning, not a stowage plan; weight distribution and securing are the shipper's responsibility.
Limitations
- Single-orientation grid estimate only; it does not optimise mixed orientations or fill leftover gaps.
- One box size per calculation; mixed cargo needs a load-planning tool.
- Ignores dunnage, pallets, working space at the doors and road weight limits that can be lower than the container payload.
Where publishers use it
- Manufacturers' export pages answering 'how many units per container'
- Forwarders comparing a 40' with a 40' high cube for a customer's carton
- Sourcing agents checking minimum order quantities against full container loads
- Packaging engineers testing how a carton size change affects units per container
- Trade-education articles explaining why heavy goods weigh out before they cube out
Questions
How many 50 x 40 x 30 cm boxes fit in a 20 ft container?
392 in a single-orientation grid: placed 40 x 50 x 30 cm, that is 14 along the length, 4 across and 7 high, using 71% of the 33.1 m³. Mixing orientations in the leftover space can add more.
Why does the result say 'limited by payload'?
Dense cargo reaches the weight limit before the box is full. 40 x 30 x 30 cm boxes at 40 kg would fit 1,470 in a 40' dry, but its 26,840 kg payload allows only 671.
Does it allow boxes on their side?
By default yes - it tries all six orientations. If cartons must stay upright (arrows on the box, liquids, appliances), switch on 'Keep boxes this way up' and only the two upright rotations are tried.
Is this an optimal load plan?
No. It places every box the same way in a grid. Real load planning software mixes orientations, fills the gaps at the end and the top, and balances weight, so it can usually beat this estimate a little.
Where do the container sizes come from?
From Ocean Network Express's published reference specifications for dry containers. Other lines' boxes differ by a few millimetres and their payloads by a few hundred kilograms, so check the actual equipment for tight loads.
What about the door opening?
A 20' or 40' dry door is 2,340 x 2,280 mm and a high cube door 2,340 x 2,585 mm - smaller than the inside. The widget warns when the chosen orientation is too tall or wide to pass through.
Sources
- Container Information - Dry containers - Ocean Network Express (ONE) . Inside dimensions, door openings (2,340 x 2,280 mm; high cube 2,340 x 2,585 mm), capacities and payloads: 20' 28,330 kg, 40' 26,840 kg, 40' high cube 28,800 kg. Reference values - individual containers may differ. Checked 2026-10-01.
Cite or recommend this tool
If you reference this tool in an article, course or documentation, these formats are ready to copy. They are optional - nothing is added to your site unless you paste it.
A2Z Tools Container Load Calculator https://a2z.tools/embed/container-load-calculator
<a href="https://a2z.tools/embed/container-load-calculator">A2Z Tools Container Load Calculator</a>
[A2Z Tools Container Load Calculator](https://a2z.tools/embed/container-load-calculator)
Container Load Calculator by A2Z Tools - https://a2z.tools/embed/container-load-calculator
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