Packing efficiency expresses how much of a rectangular unit you can realistically occupy with your belongings.
Boxes pack better than furniture
Uniform cartons can be stacked in dense columns. Sofas, chairs, bicycles and irregular equipment create voids and often cannot support loads above them.
Access reduces density
A completely full unit may be efficient on paper but unusable if you need to retrieve something from the back. An aisle deliberately sacrifices capacity for access.
Use a range, not false precision
For mixed household goods, calculate several scenarios—for example 60%, 70% and 80% efficiency—rather than relying on one exact percentage.
Try these quantities in the Storage Unit Size Calculator, then adjust them to your inventory.
Worked planning example
A 10 × 10 × 8 ft unit has 800 ft³ nominal volume. At 60% easy-access efficiency the usable estimate is 480 ft³ (13.59 m³); at 80% dense packing it is 640 ft³ (18.12 m³). That 160 ft³ difference is an assumption about gaps and stacking, not extra space supplied by the facility.
Common mistakes
- Applying 100% efficiency to mixed furniture.
- Stacking on delicate items to reach a calculated target.
- Confusing an efficiency reduction with a separate access allowance.
Related calculators
Frequently asked questions
What does 70% efficiency mean?
The model treats 70% of nominal cubic volume as usable for the inventory and reserves the rest for gaps and unfilled height.
Is a dense preset appropriate for regular access?
It may be inconvenient. Use an easy-access scenario and sketch routes to frequently needed items.
Does efficiency account for weight limits?
No. Safe stacking, floor loads and the strength of supporting items need separate checks.