What Is GSM? Fabric Weight Guide

If you've shopped for heavyweight basics, you've probably seen the term "GSM" — but what does it actually mean, and why does it matter?

What GSM Stands For

GSM stands for grams per square meter. It measures how much a one-square-meter piece of fabric weighs. The higher the GSM, the thicker, heavier, and warmer the fabric.

For context: a typical fast-fashion T-shirt is around 130–160 GSM. Woolenmaker's lightest T-shirts start at 230 GSM, and our heaviest pieces reach 800 GSM — that's roughly 5x the weight of a standard tee.

Woolenmaker GSM Tiers

230–300 GSM · Lightweight Soft, breathable — perfect for T-shirts, warm-weather basics, and layering. Shop T-shirts →

400 GSM · Mid-heavyweight Substantial and structured — ideal for year-round sweatpants with balanced warmth. Shop 400 GSM →

420 GSM · Heavyweight — Most Popular Dense and warm — our most popular tier for hoodies, shorts, and everyday sweats. Shop Hoodies → · Shop Shorts →

460 GSM · Extra Heavyweight Very thick and structured — built for cold weather and a premium feel. Shop Zip Jackets →

500 GSM · Ultra-heavyweight Maximum density — for extreme warmth and statement pieces. Shop 500 GSM →

800 GSM · Maximum Weight Extremely thick — specialty and collectible pieces from the WOOL collection. Shop WOOL Collection →

How to Choose Your GSM

For everyday wear Start with 400–420 GSM. This is the sweet spot — warm enough for cooler days, breathable enough for year-round use. Our LINDEN collection lives in this range.

For cold weather Go with 460–500 GSM. Our zip jackets at 460 GSM have YKK zippers and butter fleece lining — they're built for layering.

For summer Our 230–300 GSM T-shirts and shorts are heavyweight by industry standards but lightweight within our range — perfect for warm weather.

For maximum weight The WOOL collection features pieces up to 800 GSM — extremely thick, structured fabric for those who want the heaviest possible basics.

Why GSM Matters More Than Price

Two hoodies can cost the same but feel completely different. A 180 GSM hoodie is thin and flimsy. A 460 GSM hoodie has structure, weight, and warmth that you can feel the moment you put it on.

At Woolenmaker, we use GSM as the primary way to describe our products because it tells you more about what you're actually getting than any marketing term ever could.

All Woolenmaker Fabrics Are 100% Cotton

Most of our products use 100% cotton heavyweight fleece — not the thin jersey you'll find elsewhere. The only exception is our Scuba line, which uses a 70% cotton / 30% spandex blend for added stretch.

Our selvedge denim is 13.5oz raw selvedge — 100% cotton, unwashed, designed for natural fading over time.

Care Tips for Heavyweight Cotton

Wash cold — hot water can cause shrinkage in heavyweight cotton
Hang to dry — this is preferred; tumble dry low if needed
Don't bleach — it damages cotton fibers
Raw denim — avoid washing until fully broken in for the best fade results

Check each product page for specific care instructions.

Ready to Feel the Difference?

Browse our collections by GSM:

400 GSM · 420 GSM · 460 GSM · 500 GSM

Or start with our bestselling Baggy Sweatpants — 460 GSM heavyweight cotton, from $40.

What Is GSM? The Complete Guide to Fabric Weight