Container Load Calculator: How Many Boxes Fit in a Container
Find how many cartons fit in a 20 ft, 40 ft or 40 ft high cube container, checked against payload, with the loading layout and volume used.
Before you book a container it helps to know a geometric estimate of carton capacity. This calculator takes one carton size and weight, tries every way of turning the carton, and also tests a mix of two orientations along the container length to use the gap left at the doors. It then checks the count against the payload so you can see whether space or weight runs out first.
How to use this tool
- Choose the container type, or Custom and enter its inside dimensions.
- Pick metric or imperial units and enter the carton length, width, height and gross weight.
- Tick "Keep cartons upright" if the cartons must not be laid on their side.
- Optionally enter your own payload limit and the number of cartons in the order.
Formula
Cartons = n₁ × ⌊W ÷ w₁⌋ × ⌊H ÷ h₁⌋ + ⌊(L − n₁ × l₁) ÷ l₂⌋ × ⌊W ÷ w₂⌋ × ⌊H ÷ h₂⌋
L, W and H are the inside dimensions; l, w and h are the carton dimensions in the chosen orientation (1 for the first block of slices, 2 for the rest). The weight limit is ⌊payload ÷ carton weight⌋, and the answer is the smaller of the two counts.
Example
Cartons of 60 × 40 × 40 cm weighing 12 kg in a 20 ft container (inside about 589.8 × 235.2 × 239.3 cm): with the 60 cm side along the length, 9 slices of 5 × 5 = 25 cartons use 540 cm. The remaining 49.8 cm holds one more slice with the carton turned, 3 × 5 = 15 cartons. That is 240 cartons weighing 2,880 kg, so space runs out long before the typical 28,380 kg payload, and the cartons fill about 69% of the internal volume.
Frequently asked questions
Why is the volume used well below 100%?
Cartons rarely divide evenly into the container, so gaps remain along the walls and under the roof. Small changes to the carton size can add whole rows; try a centimetre less in one dimension and compare.
What payloads are used for the standard containers?
The representative Triton presets use 28,380 kg for a 20 ft, 28,960 kg for a 40 ft and 28,800 kg for a high cube. Check the actual container rating and road limits. These are sample equipment specifications, not universal allowances.
Can I plan mixed carton sizes?
This plans one carton size with at most 10,000 cartons along any axis. Its two-block search is not a global packing optimum. Door clearance, dunnage, box strength and securement require separate checks; volume alone cannot prove mixed cargo fits.
Sources
Last updated: 2026-10-30