GSM Is the Real Number
Fabric weight is measured in GSM — grams per square meter — and it's the one objective number behind words like "heavyweight." A basic tee typically runs 140–180 GSM. A genuinely heavyweight hoodie or crewneck runs 350–450+ GSM. Everything in between is "midweight," which is where most mass-market fleece actually lives despite what the tag says.
Higher GSM means more fiber per square inch, which is what gives a heavyweight piece its structure, its drape, and its durability — it's not just "thicker," it behaves differently on the body and holds up to more wear.
Why It Actually Matters to You
Heavier fabric holds its shape better wash after wash, resists pilling longer, and drapes with real structure instead of clinging or going limp. It's also warmer for the same reason — more material means more insulation. That's the whole case for paying more for genuinely heavyweight fleece instead of a lighter piece with the same silhouette.
The trade-off is that heavyweight pieces cost more to make and take longer to dry, which is exactly why a lot of cheaper "heavyweight" product on the market isn't, in GSM terms, actually heavyweight at all.
How to Tell by Feel
Without a scale, you can still tell a lot by hand: genuine heavyweight fleece has real substance and doesn't go see-through when stretched gently. Held up to light, a lightweight piece shows daylight through the weave; a true heavyweight one doesn't. That simple test tells you more than any hang tag claim.
Every heavyweight piece at The Film Photographer of San Francisco is genuinely in that 350+ GSM range — not a marketing word, an actual spec. If you want the exact number on a specific piece, text (415) 573-FILM and we'll pull it.