GSM Explained: How to Choose the Right Fabric Weight for Your Garment

GSM — grams per square metre — is the standard measure of how heavy and dense a fabric is. It's one of the first specs you'll be asked to pick when starting a project, and it's also one of the most misunderstood: a lot of first-time brands assume higher GSM simply means better quality. It doesn't. Here's what the number actually tells you, and what we actually recommend by product type.

The general bands

• Lightweight (120–180 GSM): breathable, soft-draping, best suited to warm-climate basics
• Medium (180–250 GSM): the most common range for everyday tees — a balance of comfort and structure
• Heavy tee (240–300 GSM): substantial, structured feel, holds its shape through washing — the range most premium streetwear leans on
• Fleece/hoodie (300–500+ GSM): warmth and body for outerwear and cold-weather pieces

What we actually recommend, by product

These general bands are a starting point, but the real answer depends on what you're making. Here's where we typically land:

• Summer tops: around 220 GSM
• Oversized tees: 250–300 GSM, for the heavier drape and structure that style calls for
• Fleece/outerwear: 300, 360, or higher — this one depends heavily on the geographic market you're selling into. A brand shipping to a colder climate needs a heavier fleece than one selling in a warm-climate market, even for the same silhouette.
• Sports shorts: 180 GSM for knitted, 140 GSM for woven — the construction type changes the right number, not just the product category
• Loungewear pants: 240–250 GSM

Performance wear is the exception — GSM isn't the main spec

For performance wear, our sweet spot is 160–180 GSM, but honestly, GSM takes a back seat here to the fabric's actual properties — moisture-wicking (dryfit), antimicrobial treatment, and how the fabric performs under movement and sweat matter more than the raw weight number. If you're building a performance piece, the conversation should be about those properties first, GSM second.

All of the above are starting points, not fixed rules — any GSM, treatment, or fabric structure can be developed to match what a specific brand actually needs, including working with a brand to develop their own fabric idea from scratch.

Higher GSM does not mean better quality

This is worth being direct about: GSM measures weight, not quality. A heavier fabric made from short, coarse, poorly-spun fibers can feel rougher and wear out faster than a lighter fabric made well. Weave and knit density, fiber quality, and finishing treatments all affect how a fabric actually performs and feels — GSM is one input, not the whole answer. Don't choose a GSM number because it sounds premium; choose it because it's right for what the garment needs to do.