Heavyweight black hoodie - what GSM means in a hoodie

أكتوبر 14, 2026

What Does GSM Mean in a Hoodie? Weight, Explained

GSM stands for grams per square metre. It is the weight of one square metre of a garment's fabric, and it is the single most useful number for judging a hoodie before it arrives. A 500 GSM hoodie is made from fabric that weighs 500 grams per square metre — substantially heavier cloth than the 280–320 GSM used in most standard hoodies. Higher GSM generally means a denser, warmer, more structured garment; lower GSM means a lighter, softer, more flexible one. Neither is automatically better. The right weight depends on when and how you intend to wear it.

GSM, defined properly

Fabric weight is measured by cutting a known area of cloth — conventionally one square metre — and weighing it in grams. The result describes the fabric only, not the finished garment: two hoodies in the same size can weigh noticeably different amounts in total if one is oversized or longer, even at identical GSM. What GSM tells you is the density of the material itself, and from density you can predict a great deal: how the hoodie hangs, how warm it feels, how it holds its shape through a day, and how it behaves in the wash.

It is worth separating GSM from thickness. The two are related but not identical. A fleece-backed fabric can feel thick while weighing less than a tightly woven flat fabric, because loft traps air without adding mass. GSM measures mass. When a brand publishes it — and many do not — it is giving you the one specification that cannot be dressed up with photography.

The hoodie weight bands, in plain terms

Hoodies cluster into recognisable bands:

Under 300 GSM — lightweight. Closer to a heavy T-shirt or sweatshirt jersey. Useful as a summer layer or under a coat, but it drapes softly, shows what is underneath, and offers modest warmth on its own.
300–380 GSM — the standard high-street hoodie. Warm enough for autumn, flexible, easy to wash and dry. Most hoodies sold in Britain sit here, which is why most hoodies feel much the same.
380–450 GSM — heavyweight territory. The fabric holds a shape, the hood sits up rather than collapsing, and the garment reads as outerwear rather than loungewear.
450 GSM and above — genuinely heavy cloth. Pieces in this band are cut deliberately, feel substantial in the hand, and are usually fleece-lined or brushed inside to make the weight comfortable rather than stiff.

For the full picture of how the heavier bands compare in wear, our guide to the best heavyweight hoodies for UK men works through fit, lining and styling in more depth.

A worked example: 500 GSM

The clearest way to understand a number is to hold it against a real garment. The Brockley oversized heavyweight hoodie is made from 500 GSM fabric in a cotton and polyester blend, with a fleece-lined interior. In practice, that specification produces a particular set of behaviours:

Drape: the fabric falls in heavier folds and keeps them. An oversized cut at 500 GSM looks intentional — volume with structure — rather than slouchy.
Warmth: density plus a fleece lining means the hoodie works as a genuine outer layer in cold weather, not just a mid-layer.
Hood behaviour: a hood cut from heavy fabric holds its shape around the neck instead of lying flat against the back. The Brockley's hood is finished without drawcords, which only works when the cloth has enough body to sit properly on its own.
Shoulders: dropped shoulders need fabric with substance; in light cloth they simply look like a poor fit.

None of this makes 500 GSM "the best" weight in the abstract. It makes it the right weight for a specific design: oversized, fleece-lined, worn as the top layer.

Does heavier always mean better quality?

No — and this is the point where GSM is most often misread. Weight is a design choice, not a quality grade. A 280 GSM hoodie in a well-made loopback cotton can be a better garment than a 450 GSM hoodie in a poor fabric with loose stitching. GSM tells you nothing directly about fibre quality, seam construction, or how the garment was cut.

What weight does correlate with, honestly stated:

Opacity — heavier fabric is rarely see-through and sits better over a T-shirt.
Shape retention — dense fabric resists the stretched cuffs and sagging body that light hoodies develop.
Warmth per layer — more material, more insulation, especially with a brushed or fleece interior.
Drying time — the honest trade-off. Heavy fabric holds more water and takes longer to dry. A 500 GSM hoodie is not the garment to wash the night before you need it.

Judge a hoodie on GSM plus fit, fibre and construction together. A brand that publishes the number is at least giving you one hard fact to start from.

How to use GSM when you are shopping

Find the number. Look in the product details or specifications. If a hoodie is described as "heavyweight" with no GSM anywhere, you are being asked to take the word on trust.
Match the band to the job. Layering under a coat: 300–380 GSM. Wearing as the main outer layer in winter: 400 GSM and above, ideally lined.
Check the fit against the weight. Heavy fabric in a slim cut can feel restrictive; heavy fabric is usually paired with regular or oversized cuts for a reason.
Check the fibre blend alongside it. Cotton brings softness and breathability; polyester in a blend adds resilience and helps the fabric hold its shape. The Brockley's cotton and polyester blend at 500 GSM is a typical heavyweight formula.
Plan the wash. Heavier garments wash perfectly well cold and gentle, but allow proper drying time — flat or on a sturdy hanger once mostly dry, never left bunched.

Frequently asked questions

What GSM is a good heavyweight hoodie?

Most people mean 400 GSM or above when they say heavyweight. At 380–450 GSM a hoodie gains real structure and warmth; at around 500 GSM, like the Brockley, it behaves as a proper outer layer in British winter weather — best with a fleece or brushed lining so the weight feels comfortable.

Is 500 GSM too heavy for everyday wear?

Not in the colder half of the year. A 500 GSM hoodie is warm enough to replace a light jacket in autumn and winter, which is the point of the weight. In summer, or layered under a close-fitting coat, a lighter fabric will be more comfortable.

Does GSM affect how a hoodie washes?

Yes, mainly through drying time. Dense fabric absorbs more water and dries more slowly, so wash heavy hoodies with time to spare and dry them flat or well supported. The washing itself is unchanged: cold, gentle, inside out is a sound default for heavy cotton blends.

Can you tell GSM without a label?

Approximately. Hold the garment: heavyweight fabric feels dense rather than lofty, the cuffs and hem have substance, and the hood keeps its shape when the garment is held up. But feel is an estimate — the published number is the fact, which is why it is worth looking for.

Is a higher GSM hoodie always warmer?

Usually, but lining matters as much as weight. A fleece-lined 400 GSM hoodie can feel warmer than an unlined 480 GSM one, because the lining traps air against the body. Read GSM and lining together before you judge warmth.