---
title: "GSM"
description: "Definition of GSM (grams per square metre) for bedding and mattress fabrics."
url: "https://bedguide.co.uk/glossary/gsm/"
category: "glossary"
primary_entity: "GSM grams per square metre"
date_published: 2026-08-03
date_modified: 2026-08-03
---

# GSM

> GSM means grams per square metre. It tells you how heavy a fabric or fibre is for its area. Higher GSM can feel denser. It does not measure spring tension or prove a mattress is better. Compare GSM only within the same material type.

**Definition.** Grams per square metre — a weight measure for fabric or fibre used on bedding and some mattress cover or fill labels.

Also called: grams per square metre.

See also [upholstery depth and GSM](/mattresses/upholstery-depth-and-gsm).

---

Source: https://bedguide.co.uk/glossary/gsm/ · BedGuide — educational encyclopedia, no affiliate commission. Facts checked against official sources where possible; see https://bedguide.co.uk/editorial-policy. Report an error: https://bedguide.co.uk/corrections.