# Caliper

> Caliper is the measured thickness of a sheet material, commonly expressed in millimetres or micrometres.

Canonical: https://dielinemaker.com/glossary/caliper
Last updated: 2026-10-26

Materials

## What it means in packaging

Board thickness influences panel offsets, folds and assembled fit. It is different from grammage: two papers with the same mass per square metre can have different thicknesses because their composition and density differ.

## A practical example

Switching to thicker board can tighten a tuck closure even when the requested inside box dimensions stay the same.

## What to check

Use the supplier’s stock specification or a measured sample. Do not derive caliper from gsm alone.

## Use it in your project

- [Choose board, caliper and finishes](https://dielinemaker.com/learn/materials-and-finishes)
- [Inside, outside and manufacturing dimensions](https://dielinemaker.com/learn/box-size-calculator)

## Related terms

- [Grammage (gsm)](https://dielinemaker.com/glossary/grammage) — Grammage is the mass of a sheet material per unit area, normally stated in grams per square metre (g/m² or gsm).
- [Inside dimensions](https://dielinemaker.com/glossary/inside-dimensions) — Inside dimensions describe the space within an assembled package, rather than its external footprint.
- [Corrugated board](https://dielinemaker.com/glossary/corrugated-board) — Corrugated board combines one or more fluted paper layers with flat liners to create a lightweight structural sheet.

## Related

- [Packaging glossary](https://dielinemaker.com/glossary)