A base footprint is incomplete
A container can widen toward its rim or have a lid that projects beyond its walls. A handle, latch or hinge may add another projection. Use the largest outside length, width and height of the complete stored item as the starting bounding box.
An internal dimension answers whether contents may fit inside the bin. It is not the right number for deciding whether the bin passes through a cupboard opening. Keep interior and exterior measurements on different lines in your notes.
Name the configuration
Record whether the lid is fitted and whether handles are raised, folded or otherwise positioned according to the product instructions. A dimension measured with a component removed may not describe the item you intend to carry or store.
Do not subtract a projection just because it looks flexible. The calculator treats its inputs as a rigid rectangular envelope and does not model deformation. If a manufacturer provides only a nominal capacity, obtain the relevant external dimensions rather than deriving them from that capacity.
Check the actual purchase unit
Some listings describe a multi-pack, and packaging measurements can appear alongside item dimensions. Verify which numbers describe one complete container. The Sterilite reference on our gear page is explicitly a twelve-pack, not a promise that twelve boxes fit a particular RV.
Keep the item model, source and measured configuration with the result. A bounding-box estimate is still limited by uncertain measurements and real obstructions. It does not judge lid retention, carrying strength or vehicle load limits.
Related gear notes
Worked examples and organizational methods are our own planning analysis, not product tests. Follow exact vehicle and equipment documentation. No load rating, installation or travel-security assessment is provided. Our research method.