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What is GSM in Fabric? The Complete Guide for Clothing Buyers

GSM (grams per square metre) determines fabric weight and quality. Learn what GSM means, how to choose the right GSM for different garments, and how it affects your clothing costs.

What Does GSM Mean in Fabric?

GSM stands for Grams per Square Metre — it's the standard measurement of fabric weight. A higher GSM means heavier, denser fabric; a lower GSM means lighter, more breathable fabric.

Formula: GSM = Weight of fabric (grams) ÷ Area (square metres)

GSM is the single most important spec buyers need to define, yet it's often overlooked in tech packs. Getting it wrong leads to fabric substitutions and product failures.

GSM Ranges by Fabric Type

Different fabric types have different typical GSM ranges. Here's a practical reference:

Lightweight (80-150 GSM)

• T-shirts (summer): 120-150 GSM
• Chiffon blouses: 80-100 GSM
• Lining fabrics: 80-120 GSM
• Thin jersey knits: 120-140 GSM

Best for: Warm weather, layering pieces, inner lining

Medium Weight (150-300 GSM)

• Standard T-shirts: 160-200 GSM
• Polo shirts: 180-220 GSM
• Casual shirts (woven): 120-180 GSM
• Leggings/activewear: 200-280 GSM
• Denim (light): 200-280 GSM

Best for: Year-round basics, workwear, sportswear

Heavyweight (300-600+ GSM)

• Hoodies/sweatshirts: 280-450 GSM
• Fleece jackets: 300-400 GSM
• Denim (heavy): 350-500 GSM
• Outerwear/coats: 400-600 GSM
• Canvas workwear: 400+ GSM

Best for: Cold weather, outerwear, workwear durability

How GSM Affects Your Business

1. Cost impact

Fabric typically accounts for 40-60% of garment cost. Higher GSM = more material = higher cost. A 50 GSM increase can raise garment cost by 8-15%.

2. Quality perception

Buyers associate heavier GSM with quality. A 160 GSM T-shirt feels premium versus a 100 GSM shirt that feels thin and cheap. However, heavier isn't always better — a 300 GSM summer T-shirt would be unwearable.

3. Compliance

Some retail channels (e.g., Walmart, Target) have minimum GSM requirements for certain product categories.

GSM by Product Category: Quick Reference

Product	Recommended GSM
Summer T-shirt	150-180
Premium T-shirt	200-220
Hoodie	300-380
Polo Shirt	200-230
Activewear leggings	220-280
Dress shirt (woven)	110-140
Jeans (light)	230-280
Jeans (heavy)	350-450

How to Specify GSM in Your Tech Pack

Always specify GSM in your tech pack with a ±5% tolerance. Example spec:

• Fabric: 100% combed cotton jersey
• GSM: 200g/m² (±10g tolerance)
• Width: 160cm

Without a GSM spec, factories will use their standard fabric, which may not match your expectations.

How QICHENG Handles Fabric Specifications

Our sourcing team works with certified fabric mills and conducts GSM testing before bulk cutting. We provide fabric swatches before production confirmation so you can verify weight and hand feel. We also stock standard fabric ranges (150-400 GSM) to reduce lead time for repeat orders.

Conclusion

GSM is one of the most important fabric specifications you'll work with. Understanding GSM ranges helps you make informed sourcing decisions, control costs, and ensure your products meet customer expectations. Always include GSM in your tech pack to avoid surprises during production.