Fabric Weight (GSM): What the Numbers Mean

What Is GSM and How Is It Measured?

GSM (grams per square meter) is the universal textile industry standard for measuring fabric weight. GSM tells you how much one square meter of fabric weighs in grams — the higher the number, the heavier the fabric. This single measurement directly affects how a fabric performs in your finished product, from how it drapes and feels against skin to how much liquid it can absorb.

Key Concept: GSM measures weight, not thickness. A tightly knitted fabric can be thin but heavy (high GSM), while a lofty fleece can feel thick but weigh relatively little (low GSM). Always check GSM alongside other specifications when evaluating a fabric for your project.

Why GSM Matters for Your Project

Absorbency: Higher GSM generally means more fiber mass available to hold liquid — critical for absorbent cores in hygiene and medical products
Drape: Lower GSM fabrics drape more fluidly for garments and linings; higher GSM fabrics hold structure for pads, protectors, and industrial uses
Durability: Heavier fabrics typically withstand more wash cycles and mechanical stress before showing wear
Hand-feel: GSM influences how a fabric feels in your hand — lighter fabrics feel softer and more delicate, heavier fabrics feel more substantial
Bulk: Higher GSM adds thickness to multi-layer products — important when balancing performance against comfort and wearability

All fabric specifications, including GSM, may vary ±10% due to textile industry manufacturing standards. For details on why variation occurs, see Specifications, Variation & Shrinkage.

Heavier is not always better. A 400 GSM absorbent core delivers maximum capacity — but in a slim-fit incontinence brief, that bulk may compromise comfort and discretion. Match your GSM to the product's real-world requirements, not just the highest number available.

Choosing Weight for Multi-Layer Products

Multi-layer products — cloth diapers, incontinence pads, menstrual products, mattress protectors — require different GSM weights at each layer. The layer's purpose determines the ideal weight, not a single "best" GSM across the entire product.

Layer-by-Layer Weight Guide

Stay-dry surface layer (skin contact): Lightweight, under 150 GSM — ProCool® or TransWICK® wicking fabrics that pull moisture away from skin quickly without adding bulk
Absorbent core layer (liquid storage): Mid-weight to heavyweight, 200–400+ GSM — Zorb® fabrics engineered specifically for maximum liquid retention per layer; higher GSM = more capacity per layer, fewer layers needed
Waterproof barrier layer (leak protection): Light to Mid-weight, 100–250 GSM — ProSoft® PUL fabrics that block liquid transfer while remaining flexible enough for comfortable wear

Reducing bulk without sacrificing performance: Zorb® 3D and 4D fabrics achieve high absorbency at lower layer counts than traditional materials. One layer of Zorb® can replace multiple layers of cotton or flannel — reducing total product thickness while maintaining or improving capacity.

When designing multi-layer products, calculate your total stack GSM by adding each layer's weight. A typical three-layer reusable pad might combine a 120 GSM wicking top, a 300 GSM absorbent core, and a 200 GSM waterproof barrier — totaling approximately 620 GSM across the full stack. Adjust individual layer weights up or down based on whether your priority is maximum absorbency, minimum bulk, or a balance of both.

The GSM values listed on each product's Specs tab reflect nominal weight. Fiber content also affects performance at any given GSM — for how different fibers behave and how different fiber types affect performance within each layer, see Fiber Content Guide: Cotton, Bamboo, Polyester, Merino & Blends..