Why Fabric GSM Is Allowed at ±5% Tolerance

In the textile and garment industry, GSM (Grams per Square Meter) is a key parameter used to define the weight and quality of a fabric. GSM influences fabric feel, durability, cost, and garment performance. However, in most buyer specifications, fabric GSM is not fixed at an exact value; instead, a tolerance of ±5% is allowed.

This raises a common question: Why is fabric GSM allowed at ±5%?

 

1. Natural Variations in Fabric Production

Fabric manufacturing is a continuous process involving knitting or weaving, dyeing, washing, and finishing. Each stage introduces minor variations due to:

• Machine tension differences
• Loop length variation (especially in knitted fabrics)
• Production speed and settings

Because of these factors, maintaining an absolutely fixed GSM across bulk production is technically unrealistic. The ±5% tolerance accounts for these natural variations.

 

2. Yarn Properties Affect Fabric GSM

Even when the same yarn count is used, yarn properties can vary slightly due to:

• Moisture absorption
• Twist inconsistency
• Fiber length and uniformity differences

These small yarn variations directly impact fabric weight per square meter. Allowing a ±5% GSM range ensures consistent quality without unnecessary rejection.

 

3. Effect of Dyeing, Washing, and Finishing

Fabric GSM often changes after wet processing due to:

• Shrinkage during dyeing and washing
• Mechanical compaction or stretching in finishing
• Chemical treatments such as enzymes or softeners

A fabric may increase or decrease in GSM after finishing compared to its grey state. Since these changes cannot be controlled with absolute precision, GSM tolerance is essential.

 

4. Environmental Influence on GSM Measurement

GSM testing results can vary depending on:

• Temperature
• Humidity

Fabric absorbs moisture from the surrounding air, which slightly increases its weight. Different testing environments can produce different GSM results for the same fabric. The ±5% tolerance allows for fair and realistic evaluation.

 

5. No Significant Impact on Garment Performance

A ±5% difference in GSM does not usually affect:

• Fit
• Comfort
• Strength
• Appearance

For example:
180 GSM ±5% = 171–189 GSM

Within this range, the fabric performs as expected for most garments such as T-shirts, polo shirts, and casual wear.

 

6. Production Efficiency and Cost Control

Requiring exact GSM with zero tolerance would lead to:

• High rejection rates
• Increased fabric wastage
• Higher production costs

The ±5% tolerance balances quality control with commercial practicality, helping both buyers and manufacturers manage costs efficiently.

 

7. Internationally Accepted Quality Practice

The ±5% GSM tolerance is a globally accepted standard across knitted and woven fabrics. It aligns with common buyer quality standards and international testing practices, ensuring smoother communication and consistent expectations throughout the supply chain.

 

Conclusion

Fabric GSM is allowed at ±5% tolerance because:

• Minor variations are unavoidable in textile processing
• Yarn, wet processing, and environment affect fabric weight
• Garment performance remains stable within this range
• It reduces rejection while maintaining quality and cost efficiency

In summary, ±5% GSM tolerance is a practical and industry-approved approach that ensures reliable quality without compromising production feasibility.