How to calculate how many cartons fit in a container
To calculate container loading, divide each inside dimension of the container by the matching carton dimension, round down, and multiply the three results. Try the other carton orientations and keep the best. Then check that the total weight stays under the container payload. For example, 60 × 40 × 40 cm cartons in a 40ft high cube give ⌊1203 ÷ 60⌋ × ⌊235 ÷ 40⌋ × ⌊269 ÷ 40⌋ = 20 × 5 × 6 = 600 cartons. Mixing orientations raises it to 660.
Step by step
- Measure one packed carton. Measure the outside length, width and height of one packed carton, and its gross weight. Round up to the next centimeter; bulging cartons take more space than their nominal size.
- Calculate total volume and weight. Multiply length × width × height in meters to get CBM per carton, then multiply by the quantity. Do the same for weight. This tells you roughly which container size you need.
- Work out cartons per layer. Divide the container length and width by the carton length and width, round both down and multiply. Try the carton turned 90° as well; sometimes a row turned the other way fills the leftover gap.
- Work out the number of layers. Divide the inside height by the carton height and round down. If cartons may lie on their side, try the other dimensions as the height too.
- Check weight and stacking. Multiply the carton count by the carton weight and compare with the container payload. Make sure the bottom cartons can carry the weight of all the layers above them.
- Verify with a 3D loading plan. Hand math misses mixed orientations and mixed carton sizes. Enter the cartons in a load calculator to get the exact count, the container comparison and a loading sequence to share with the warehouse.
Worked example
| Orientation (L × W × H) | Along length | Across width | Layers | Total |
|---|---|---|---|---|
| 60 × 40 × 40 cm | 20 | 5 | 6 | 600 |
| 40 × 60 × 40 cm | 30 | 3 | 6 | 540 |
| 40 × 40 × 60 cm | 30 | 5 | 4 | 600 |
| Mixed orientations (3D plan) | — | — | — | 660 |
40ft high cube, inside 1203 × 235 × 269 cm. The single-orientation methods leave a gap along one wall; the 3D plan fills it with cartons turned the other way.
Common mistakes
- Using outside container dimensions. Always use the inside dimensions (see container sizes).
- Dividing total CBM by container CBM. This ignores gaps and overestimates capacity by 10–25%.
- Forgetting the door. Pallets and tall items must pass through a door that is lower than the inside height.
- Ignoring weight. Dense cargo reaches the payload limit before the container is full.
Frequently asked questions
What is the formula for container loading?
Cartons = ⌊container length ÷ carton length⌋ × ⌊container width ÷ carton width⌋ × ⌊container height ÷ carton height⌋, using inside dimensions. Try each carton orientation and keep the highest result, then check weight.
Can I just divide total CBM by container CBM?
Only as a rough first check. Real loads leave gaps, so plan for about 75–90% of the container volume.
How do I calculate loading for mixed carton sizes?
Load the largest and heaviest cartons first, then fill the remaining space with smaller ones. A 3D load calculator does this automatically.