Wholesale Knitwear UK — What GSM Should You Choose for Your Brand?

1. What Is GSM and Why Does It Matter?

GSM — grams per square metre — is the fundamental unit of fabric weight used across the entire apparel industry. It tells you how much a one-square-metre piece of the fabric weighs in grams. That single number communicates density, warmth, structure, hand-feel, and durability in a way that fabric names alone cannot.

When buyers order wholesale knitwear without specifying GSM, they are essentially leaving the most important product variable undefined. A supplier might produce your crew necks at 220 GSM when your brand positioning demands 300 GSM — and the result is a garment that disappoints at the exact moment a customer first touches it.

For UK clothing brands buying knitwear wholesale — whether crew neck sweatshirts, oversized drop-shoulder styles, quarter-zips, or structured knit tops — understanding how to specify GSM correctly is as important as specifying the colour or the size range. It determines the garment's perceived value, its seasonal appropriateness, and its durability over time.

2. The GSM Spectrum — Knitwear Weight Breakdown

The knitwear GSM spectrum spans from approximately 160 GSM for lightweight jersey constructions to 500+ GSM for ultra-heavyweight garments. Each band has a distinct character and appropriate application:

At Trade Apparel Supply, our knitwear range spans 160–500 GSM across multiple fabric compositions, giving you precise control over how your product lands in the hand — and in the mind — of your customer.

3. Matching GSM to Your Brand Positioning

GSM is not purely a technical variable — it is a brand positioning decision. Different brand archetypes demand different weight strategies. Here are the most common brand types we work with and the GSM approach that typically serves them best:

4. Fabric Composition — What Goes Into the Weight

GSM alone does not tell the full story. Two 300 GSM sweatshirts can feel entirely different depending on their fibre composition. The fibres determine the softness, breathability, durability, stretch recovery, and ethical story your brand can tell.

5. Knitwear Construction — Terry, Fleece & Loop

Beyond weight and composition, the construction method fundamentally changes how a knitwear piece looks, feels, and performs. These are the most important construction types for wholesale knitwear buyers to understand:

French Terry

French terry is a loopback jersey construction with a smooth face and uncut looped reverse. It offers a clean, contemporary aesthetic from the outside while providing comfortable softness on the skin side. French terry is the dominant construction for premium UK knitwear brands — it takes dye beautifully, maintains shape, and communicates quality without the casual association that brushed fleece carries.

Brushed Fleece

Brushed fleece has its loops cut and processed to create a soft, napped reverse surface. It is significantly warmer than French terry at the same GSM due to the increased surface area for heat retention. Brushed fleece is appropriate for cold-weather knitwear, outdoor brands, and styles where thermal comfort is the primary value proposition.

Single Jersey

Single jersey is a lighter, single-layer knit construction with a smooth face and slight stretch. At 160–200 GSM, it is the standard for premium t-shirts and lightweight sweatshirt styles. Its ability to drape and move makes it the preferred construction for fitted silhouettes.

Double Jersey (Interlock)

Interlock knit uses two interlocked jersey layers. The result is a fabric that is smooth on both sides, more stable dimensionally, and denser for its weight than single jersey. Used in premium polos, structured sweatshirts, and garments where printed or embroidered branding needs a stable base.

6. Seasonal Considerations for UK Knitwear Buyers

The UK climate creates a specific demand pattern for knitwear that differs from continental European or North American markets. Understanding this rhythm helps you buy at the right weights for the right windows.

Spring / Summer (March–August)

The UK summer market has genuine appetite for lightweight knitwear — garments you would reach for on an overcast July evening or wear as a layer into an air-conditioned office. 160–220 GSM in organic cotton or bamboo cotton occupies this space well. These are also strong layering pieces for gym-to-street transitions.

Autumn / Winter (September–February)

This is the core knitwear selling window for UK brands. From September, customers actively seek weight and warmth. 280–420 GSM serves the full range of autumn and winter knitwear needs. October and November are historically the strongest months for heavyweight knitwear sales — plan your production to arrive in-warehouse by late September.

Year-Round Positioning

Brands targeting wholesale accounts (gyms, corporate clients, independent boutiques) often want a single knitwear SKU that works across seasons. 260–300 GSM in organic cotton French terry is the professional recommendation for year-round knitwear positioning in the UK — substantial enough for autumn, light enough to wear in spring, and premium enough for any retail context.

7. How to Specify GSM When Ordering Wholesale

Ordering wholesale knitwear without a clear specification leaves too many variables in the supplier's hands. When submitting an enquiry or purchase order, include the following:

• Exact GSM target: State your desired weight (e.g., 300 GSM, not "medium weight"). If you have a tolerance range, state it: 290–310 GSM.
• Fibre composition: Specify the exact blend (e.g., 100% GOTS organic cotton, or 85/15 cotton-polyester).
• Construction type: French terry, brushed fleece, single jersey, interlock — specify explicitly.
• Certification requirements: If your brand requires GOTS, GRS, or Oeko-Tex certification, state this upfront — it affects sourcing and may affect timelines.
• Reference sample or swatch: If you have a reference garment that represents your desired quality level, share it with your supplier. Physical references eliminate ambiguity better than any written specification.
• End use: Inform your supplier how the garment will be used. Gym wear, retail display, corporate gifting, DTC — different end uses may lead to construction recommendations you wouldn't have thought to request.

8. Common GSM Mistakes and How to Avoid Them

Mistake 1: Buying on Price Rather Than Specification

Many first-time buyers choose a lower GSM without realising that a 220 GSM crew neck will feel noticeably thinner than a 300 GSM alternative — regardless of what the label says. Your customer's hands are the most honest quality audit in the supply chain.

Mistake 2: Assuming GSM Is Consistent Across Fabrics

A 300 GSM French terry feels and performs very differently from a 300 GSM brushed fleece. GSM is a weight measure — not a quality or warmth guarantee. Always specify construction alongside weight.

Mistake 3: Not Requesting a Pre-Production Sample

Approving knitwear from a catalogue image and a GSM number is a significant risk. The only reliable quality check is a physical pre-production sample. Feel it. Wash it. Wear it. Approve it in writing before bulk production proceeds.

Mistake 4: Mismatching GSM to Branding Application

Embroidery on very lightweight knitwear (sub-200 GSM) can cause puckering and distortion due to the density of the embroidery backing vs. the lightness of the base fabric. If embroidery is a core branding element of your knitwear, a minimum of 260 GSM provides a stable enough base for clean execution.

Mistake 5: Ordering One Weight for All Seasons

Brands with broader retail distribution — particularly those selling into independent boutiques — benefit from offering both a lighter spring-weight knitwear option and a heavier autumn option. A single-weight, year-round knitwear strategy often results in a weight compromise that is slightly wrong for every season rather than perfectly right for any.