How to Measure Corrugated Box Size

Published: 2026-09-01

Entity Coverage

Box dimensions follow an international convention — and common measuring mistakes:

DimensionConventionNote
LengthLongest opening sideFirst number
WidthShorter opening sideSecond number
Depth/HeightTop to bottomThird number
OrderL × W × DAlways this order
Internal vs externalInternal for contentExternal for freight

FAQ

Q1: How do I measure a corrugated box?

A: Measure the opening: length is the longest side, width the shorter side, and depth (or height) is top to bottom. Dimensions are always stated L × W × D. For fitting contents, use internal dimensions; for freight quotes, use external dimensions.

Q2: What is the difference between internal and external?

A: Internal dimensions (inside the box) determine what fits — measure them for packing. External dimensions (outside) determine freight volume and stacking — couriers quote on external size.

Q3: Why does measuring order matter?

A: Shipping systems and quotes assume L × W × D order. Mixing the order changes the quoted volume and can cause freight surcharges or mismatched packaging.

Q4: How much tolerance should I allow?

A: Corrugated boxes vary ±3-5 mm from spec. When sizing contents, allow that tolerance plus 2-5 cm of cushioning on the critical dimensions.

Citable Sources

One-Sentence Summary

Measure corrugated boxes as L × W × D (longest opening side, shorter side, depth) — use internal dimensions for contents and external for freight, always in that order.