---
title: "Upholstery Depth and GSM Explained"
description: "Simple guide to mattress upholstery depth and GSM fabric or fibre ratings used on UK bed labels."
url: "https://bedguide.co.uk/mattresses/upholstery-depth-and-gsm/"
category: "mattresses"
primary_entity: "mattress upholstery depth and GSM"
date_published: 2026-08-03
date_modified: 2026-08-03
---

# Upholstery Depth and GSM Explained

> Upholstery depth is how thick the soft layers above the support core are. GSM means grams per square metre and often rates fibre or fabric weight. Deeper upholstery can feel plusher. Higher GSM can mean a denser fill or cloth. Neither number alone proves quality. Read them with spring tension or foam density.

## Key facts

- Materials: wool and cotton fibre, foam comfort layers, cover fabrics
- Typical lifespan: 6–10 years

## Two different numbers

| Term | Measures | Useful for |
| --- | --- | --- |
| **Upholstery depth** | Thickness of soft layers above the core | Plush versus thin top feel |
| **GSM** | Mass of fabric or fibre per square metre | Comparing cloth or fill density |

## How to use them

1. Fix [support](/mattresses/spring-tension-vs-comfort-feel) for your body weight first.  
2. Then choose upholstery depth for top feel.  
3. Use GSM only to compare similar materials — not to rank whole mattresses.

## Related BedGuide entries

- [What’s inside a mattress](/mattresses/whats-inside-a-mattress)
- [Pillow-top and surface types](/mattresses/pillow-top-and-surface-types)
- [Natural fillings](/mattresses/natural-fillings-wool-cotton-horsehair)

## Frequently asked questions

### What does GSM mean on bedding or mattress fabric?

GSM means grams per square metre. It is a weight measure for fabric or fibre. A higher GSM cloth can feel denser. It does not tell you spring tension or overall mattress quality by itself.

### Does deeper upholstery make a mattress better?

Deeper upholstery often feels softer on top. Support still comes from the core. A deep soft quilt on soft springs can feel sinky. Match depth to the feel you want after support is right.

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Source: https://bedguide.co.uk/mattresses/upholstery-depth-and-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.