How to Measure Box Size: Length, Width and Depth

Getting box size right is the difference between a snug, professional package and a rattling, damaged one. Box dimensions also drive your shipping cost. Here is how to measure a box correctly and choose the right size for your product.

How box dimensions are written

Boxes are measured as Length x Width x Depth, always using the internal dimensions (the space your product sits in). Length is the longest side of the opening, width the shorter side, and depth the height from base to opening.

Internal vs external size

Always design and order to internal dimensions so your product fits. External size matters for shipping and stacking. State clearly which you mean when ordering.

Sizing for a snug fit

• Add a small tolerance (a few millimeters) so the product slides in easily.
• Account for inserts, wrapping, or void fill.
• Avoid oversizing - it wastes material and raises shipping costs.

See our right-size packaging guide.

From size to design

Correct dimensions feed straight into your dieline. See our dielines guide and the complete guide to custom printed boxes.

Frequently asked questions

Is box size internal or external?

Order to internal dimensions so your product fits; external size is for shipping and stacking.

What order are dimensions listed?

Length x Width x Depth, with length and width being the opening and depth the height.

How much tolerance should I add?

A few millimeters so the product loads easily, plus space for any insert or wrap.

Size your box right

Get a snug, cost-efficient fit. Explore our custom printed boxes or the e-commerce boxes collection.