Why fewer fit than CBM ÷ 67
A spreadsheet divides your CBM by the container volume. Real boxes leave gaps — here is why the plan needs more.
A 40ft HC is 75.8 m³ inside. People divide their list's CBM by about 67 because whole boxes never fill all of it. TrimLoad does not divide — it places every box, so the answer is the real number of containers.
Where the space goes
- Whole boxes leave strips at the walls and under the roof: 234.2 cm across takes 5 boxes of 45 cm and 9.2 cm stays empty.
- “Don't stack on top” and “Floor only” leave the space above those boxes empty.
- The payload is often reached before the space is full (heavy lines).
- Some boxes only pass the door one way, which wastes the rest of that row.
- Clearance keeps a few centimetres free on each axis.
On the plan
When the plan needs more containers than CBM suggests, a line under the plan says so: “CBM says 1.3 × 40ft HC. The plan needs 2 × 40ft HC — …” with the main reason. The summary also names what limited the plan: weight, space or door.