Single Jersey vs Interlock Fabric: Why Two T-Shirts with the Same GSM Feel Completely Different

 

Single Jersey vs Interlock Fabric: Why Two T-Shirts with the Same GSM Feel Completely Different

By Learn Easy Textile

Introduction

Have you ever picked up two T-shirts that both claimed to be 180 GSM, yet one felt soft and lightweight while the other felt thicker, firmer, and more premium?

This is a common question in the textile and apparel industry. Many buyers, students, and even some apparel professionals assume that GSM (Grams per Square Meter) is the only indicator of a fabric's quality or thickness. While GSM is an important measurement, it tells only part of the story.

The real difference often lies in fabric construction.

A 180 GSM Single Jersey fabric and a 180 GSM Interlock fabric may have the same weight, but they can look, feel, stretch, and perform very differently because they are knitted using different structures.

In this article, we'll explore the differences between Single Jersey and Interlock fabrics, explain why GSM alone isn't enough, and help you choose the right fabric for your next apparel project.

 

What Is GSM?

GSM stands for Grams per Square Meter.

It measures the weight of one square meter of fabric.

Generally:

• Lower GSM fabrics are lighter.
• Higher GSM fabrics are heavier.
• GSM helps estimate fabric weight but does not determine quality, durability, softness, or performance.

For example:

• 140 GSM – Lightweight summer T-shirts
• 160–180 GSM – Standard casual T-shirts
• 200–240 GSM – Premium or heavyweight T-shirts
• 250 GSM and above – Sweatshirts, hoodies, and winter garments

However, two fabrics with the same GSM can still feel completely different because of how they are constructed.

 

Understanding Fabric Construction

Fabric construction refers to the way yarns are knitted or woven together.

In knitted garments, the knit structure significantly influences:

• Thickness
• Softness
• Stretch
• Recovery
• Drape
• Appearance
• Durability
• Comfort

This is exactly why Single Jersey and Interlock fabrics behave differently despite having identical GSM values.

 

What Is Single Jersey Fabric?

Single Jersey is one of the most widely used knitted fabrics in the apparel industry.

It is produced using a single-knit structure, creating one smooth face and one textured back.

This construction gives the fabric excellent flexibility and breathability.

Characteristics of Single Jersey

• Lightweight feel
• Soft hand feel
• Excellent drape
• Good breathability
• Natural stretch
• Comfortable for daily wear
• Cost-effective production

Because of its structure, Single Jersey may curl at the edges when cut and usually has lower dimensional stability than Interlock.

 

Advantages of Single Jersey

Soft and Comfortable

The fabric feels smooth and comfortable against the skin, making it ideal for everyday clothing.

Excellent Breathability

Its open knit structure allows better air circulation, making it suitable for warm climates.

Better Drape

Single Jersey naturally follows body contours, giving garments a relaxed appearance.

Lower Manufacturing Cost

Since it uses less yarn than double-knit fabrics, it is generally more economical.

Versatile

Single Jersey works well for a wide range of casual garments.

 

Limitations of Single Jersey

Despite its popularity, Single Jersey has some drawbacks:

• Lower shape retention
• Edges tend to curl
• Less durable than double-knit fabrics
• Slightly lower opacity
• May stretch out over time if not properly finished

 

Common Applications of Single Jersey

Single Jersey is commonly used for:

• Basic T-shirts
• Fashion tees
• Sportswear
• Promotional garments
• Casual tops
• Sleepwear
• Undergarments

Its lightweight nature makes it especially suitable for tropical climates.

 

What Is Interlock Fabric?

Interlock is a double-knit fabric produced by interlocking two layers of knitting together.

Unlike Single Jersey, both sides of the fabric look almost identical, creating a smooth, premium appearance.

Although Interlock may have the same GSM as Single Jersey, its denser construction makes it feel thicker and more substantial.

 

Characteristics of Interlock Fabric

• Double-knit construction
• Smooth surface on both sides
• Dense fabric structure
• Better dimensional stability
• Excellent stretch recovery
• Premium appearance
• Higher durability

Because the loops are interlocked, the fabric resists curling and maintains its shape much better.

 

Advantages of Interlock

Superior Shape Retention

Garments maintain their original appearance even after repeated washing.

Better Stretch Recovery

The fabric stretches comfortably and returns to its original shape more effectively.

Premium Appearance

Both sides are smooth and attractive, making the garment look more luxurious.

Higher Durability

The dense knit structure improves resistance to wear and tear.

Better Opacity

Interlock provides better coverage because of its thicker construction.

 

Limitations of Interlock

Interlock offers many advantages, but there are some trade-offs:

• Higher production cost
• Greater yarn consumption
• Slightly heavier feel
• Longer knitting time
• Less breathable than Single Jersey in some applications

 

Common Applications of Interlock

Interlock is widely used for:

• Premium T-shirts
• Polo shirts
• Children's clothing
• Baby garments
• Uniforms
• Sportswear
• Luxury casual wear
• Fashion basics requiring better structure

 

Single Jersey vs Interlock: Comparison Table

Feature	Single Jersey	Interlock
Knit Structure	Single Knit	Double Knit
Fabric Weight	Can be the same GSM	Can be the same GSM
Thickness	Thinner	Thicker
Hand Feel	Soft and flexible	Dense and premium
Stretch	Higher natural stretch	Balanced stretch with better recovery
Shape Retention	Moderate	Excellent
Edge Curling	Yes	No
Durability	Good	Excellent
Opacity	Lower	Higher
Cost	More economical	More expensive
Yarn Consumption	Lower	Higher
Appearance	Different front and back	Smooth on both sides

 

Why Does 180 GSM Feel Different?

Imagine two fabrics:

• 180 GSM Single Jersey
• 180 GSM Interlock

Both weigh exactly 180 grams per square meter.

However, they feel different because the yarn is arranged differently.

Single Jersey distributes yarn through a single layer, producing a lighter, softer, and more flexible fabric.

Interlock distributes the same overall weight through a double-knit structure, creating a denser, thicker, and more stable fabric.

Therefore:

Same GSM ≠ Same Fabric Performance

This is one of the most important concepts every textile professional should understand.

 

Factors to Consider Beyond GSM

When selecting fabric, buyers and manufacturers should evaluate several characteristics instead of focusing only on GSM.

These include:

• Knit construction
• Fiber composition
• Yarn count
• Fabric thickness
• Hand feel
• Stretch and recovery
• Dimensional stability
• Durability
• Surface appearance
• Breathability
• Cost
• End-use requirements
• Washing performance
• Customer expectations

Considering these factors leads to better fabric selection and improved garment performance.

 

Which Fabric Should You Choose?

The ideal fabric depends on the intended application.

Choose Single Jersey if you need:

• Lightweight garments
• Soft everyday T-shirts
• Fashion apparel
• Sportswear
• Breathable summer clothing
• Cost-effective production

Choose Interlock if you need:

• Premium garments
• Better durability
• Improved shape retention
• Children's clothing
• Uniforms
• Luxury casual wear
• Higher opacity
• A more structured appearance

Neither fabric is universally better—the right choice depends on the product's purpose, budget, and customer expectations.

 

Final Thoughts

Many people judge fabrics by GSM alone, believing that a higher GSM automatically means better quality or that two fabrics with the same GSM will perform the same.

In reality, GSM only measures fabric weight. It does not describe the knit structure, thickness, softness, stretch, recovery, durability, or overall performance.

This is why a 180 GSM Single Jersey and a 180 GSM Interlock can feel like completely different fabrics despite having identical weight.

Understanding the relationship between GSM and fabric construction enables textile engineers, merchandisers, garment manufacturers, and buyers to make more informed sourcing decisions and create garments that meet both performance requirements and customer expectations.

So the next time someone says, "We only need 180 GSM fabric," remember:

180 GSM is only part of the story. Fabric construction is what truly defines how a fabric looks, feels, and performs.

 

Frequently Asked Questions (FAQs)

Is Interlock warmer than Single Jersey?

Yes. Because of its double-knit construction, Interlock is generally thicker and provides better insulation than Single Jersey.

Which fabric is more durable?

Interlock is typically more durable due to its dense knit structure and superior shape retention.

Is Single Jersey better for summer?

Yes. Single Jersey is lighter, more breathable, and often preferred for summer T-shirts and activewear.

Can Single Jersey and Interlock have the same GSM?

Absolutely. Two fabrics can have the same GSM but still differ significantly in thickness, texture, stretch, and overall performance because of their knit construction.