Use the finished package
Measure after the product, padding, tape, and closure are in place. Use the maximum outside distance across each axis, including bulges or protruding points that affect the shipping profile.
Record three perpendicular dimensions
Label the longest side length for girth checks, then record the remaining width and height. A volume calculation itself is order-independent, but carrier rules can define their own measurement rounding.
- 1Place the sealed parcel on a flat surface
- 2Measure the longest outside side
- 3Measure the other two perpendicular sides
- 4Keep the raw measurement before applying a verified rule's rounding
Separate measuring from rule rounding
Store the observed dimensions, then let the selected rule apply rounding. Premature manual rounding makes historical results difficult to reproduce when a rule changes.