When buying polyester fabric for garment production, GSM, DIA, construction and price are all important to check. But there is one other specification you shouldn't miss — fabric shrinkage.
While polyester generally has good dimensional stability, knitted polyester fabrics can experience dimensional changes depending on the garment construction, processing, finishing, heat treatment and washing.
For clothing brands, garment manufacturers and bulk fabric buyers, understanding fabric shrinkage can help prevent unexpected changes to fabric size, garment fit and fabric consumption.
In this guide, we'll discuss what fabric shrinkage means, why it occurs, how to test it and what fabric buyers should check before approving a polyester fabric for bulk production.
What Is Fabric Shrinkage?
Fabric shrinkage describes a reduction in the fabric dimensions after undergoing processes such as washing, drying, heat treatment or other finishing processes.
The change can be in:
- Length
- Width
- Or both
For example, if a fabric sample measures 100 cm before washing and only measures 98 cm after washing, the fabric has undergone a dimensional reduction.
The garment industry is particularly affected by fabric length and width shrinkage because the finished fabric dimensions can impact the end garment size and fit.
Does Polyester Fabric Shrink?
Polyester is generally known for its dimensional stability compared to many natural fibres. However, this doesn't mean that every single polyester fabric will behave in exactly the same way.
There are a number of fabric variables that can influence the dimensional behaviour of polyester fabric, including:
- Fabric construction
- Knitting process
- Fabric tension
- Finishing process
- Heat treatment
- Relaxation
- Washing conditions
- Drying conditions
- Fabric composition
This is especially true for polyester knitted fabrics used for T-shirts, sportswear, jerseys and other apparel.
Rather than assuming that polyester fabric won't shrink, it's better to test an approved sample before bulk production to get a better understanding of its actual dimensional stability.
Causes of Shrinkage in Polyester Knitted Fabric
There are several factors that can cause fabric shrinkage.
1. Knitting Tension
During the knitting process, fabric and yarn can be held under tension.
When that tension is released, the fabric can undergo dimensional changes.
This is why fabric relaxation is important before fabric cutting.
2. Heat Treatment
Heat treatment of polyester fabric can occur during various stages of the textile production process.
The heat treatment process can influence fabric dimensions and stability, which is why it is an important consideration when testing fabric.
3. Fabric Finishing
The finishing process can impact:
- Fabric width
- Fabric length
- Hand feel
- Surface appearance
- Dimensional stability
The exact outcome depends on the fabric construction and finishing process.
4. Washing and Drying
Washing and drying can affect fabric dimensions because of factors such as:
- Water temperature
- Washing method
- Mechanical action
- Drying temperature
- Drying method
As a result, fabric washing and drying conditions should be considered during fabric testing to replicate the likely conditions the finished garment will undergo.
5. Fabric Construction
Fabric construction can have a major impact on the dimensional stability of the fabric.
Different knitted constructions such as Single Jersey, Piqué, Interlock and Mesh can behave differently.
This is why fabric construction should be considered alongside GSM, DIA and other specifications when evaluating polyester knitted fabric.
👉 Read our Single Jersey vs Piqué vs Interlock vs Mesh Comparison Guide to learn more about these fabric differences.
What Is Lengthwise and Widthwise Shrinkage?
Fabric shrinkage can occur in more than one direction. Testing the fabric in both directions provides a better understanding of the dimensional changes that can occur.
Lengthwise Shrinkage
This refers to a reduction in the length of the fabric.
For example:
Before testing: 100 cm
After testing: 97 cm
The fabric length has reduced by 3 cm.
Widthwise Shrinkage
This refers to a reduction in the width of the fabric.
For example:
Before testing: 100 cm
After testing: 98 cm
The fabric width has reduced by 2 cm.
Both length and width shrinkage should be considered when evaluating a polyester knitted fabric.
How to Test Fabric Shrinkage
A basic fabric shrinkage test involves measuring a fabric sample before and after undergoing a standardised washing or processing procedure.
The exact procedure will depend on the relevant industry standard and customer requirements.
A basic procedure looks like this:
Step 1: Select a Fabric Sample
Choose a fabric sample from the polyester fabric you want to test.
Step 2: Mark the Measurement Points
Mark a set of measurement points in both length and width.
For example:
Length: 50 cm
Width: 50 cm
Step 3: Wash or Process the Sample
Wash or process the fabric sample according to the procedure you want to test.
Step 4: Dry the Sample
Dry the fabric sample according to the selected procedure.
Step 5: Measure Again
Measure the same points to see what changes have occurred.
You can then use the results to calculate fabric shrinkage.
How to Calculate Fabric Shrinkage
The basic formula for fabric shrinkage is:
Shrinkage % = (Original Measurement − Final Measurement) ÷ Original Measurement × 100
Example
Suppose you have a fabric sample with:
Original length = 100 cm
After undergoing the test procedure:
Final length = 97 cm
Therefore:
(100 − 97) ÷ 100 × 100 = 3%
The lengthwise shrinkage is therefore 3%.
You can apply the same calculation to the width.
Why Length and Width Shrinkage Matters in Garment Production
If you cut your garment pattern according to the original fabric dimensions and the fabric changes during processing, the final measurements may not match the original pattern.
This can be an issue for:
- Garment length
- Chest width
- Sleeve length
- Body proportions
- Overall garment fit
When you're making hundreds or thousands of garments, even small differences in length or width can add up.
That's why fabric shrinkage should always be considered before bulk fabric cutting for garment production.
How Shrinkage Affects Fabric Consumption
Fabric shrinkage isn't only an issue for garment sizing. It can also affect fabric consumption.
If you know the fabric dimensions will change, you need to factor this into your fabric planning.
When fabric width changes, it can impact how many metres of fabric you need to cut for a given width.
This is why fabric buyers and manufacturers should consider:
- GSM
- DIA
- Finished width
- Shrinkage
- Fabric construction
- Garment pattern
- Marker efficiency
when planning fabric consumption rather than looking at just one specification.
👉 You can also read our What Is Fabric DIA? Complete Guide to Width, Cutting & Fabric Consumption guide to learn more.
Fabric Relaxation and Shrinkage in Polyester Fabric
Fabric relaxation is particularly important when working with fabric that was under tension during the knitting process.
This includes most knitted polyester fabrics.
If fabric is cut before undergoing fabric relaxation, the dimensional change can affect garment measurements.
The extent of relaxation required will depend on the fabric, so always follow the appropriate production procedure for the fabric you're working with.
Does GSM Affect Polyester Fabric Shrinkage?
GSM and fabric shrinkage describe two completely separate properties of fabric.
GSM refers to the weight of the fabric, while fabric shrinkage refers to the change in fabric length and width after a specific process.
A higher GSM doesn't necessarily indicate higher or lower fabric shrinkage.
Other factors such as:
- Fabric construction
- Yarn
- Fibre composition
- Knitting density
- Finishing
- Heat treatment
can influence the dimensional stability of a fabric.
👉 To learn more, read our Complete Guide to Fabric GSM.
Does DIA Affect Polyester Fabric Shrinkage?
DIA and fabric shrinkage describe two completely different properties of fabric.
DIA refers to the tubular dimension of knitted fabric, while fabric shrinkage refers to dimensional changes in length and width after a specific process.
If the fabric dimensions change significantly, it can impact the usable fabric width and therefore the cutting calculations.
This is why fabric buyers should consider DIA, finished width and shrinkage when sourcing knitted fabric.
How Different Polyester Fabrics Behave Differently
Not every polyester knitted fabric behaves the same way.
Single Jersey, Piqué, Interlock and Mesh all have different knitted constructions.
As a result, their dimensional stability can be different.
This is why it's important to test a fabric sample rather than making assumptions about how a particular polyester fabric will behave.
How to Control Fabric Shrinkage
While fabric shrinkage can't be eliminated from every fabric, there are steps that manufacturers can take to help control dimensional changes.
Some of the most important steps include:
- Testing fabric before bulk production
- Allowing knitted fabric to relax before cutting
- Controlling processing conditions
- Following appropriate finishing procedures
- Accounting for expected dimensional change during pattern development
- Maintaining consistency between approved samples and bulk fabric
The specific steps will depend on the fabric construction.
Common Mistakes When Buying Polyester Fabric With Shrinkage
1. Assuming That Polyester Never Shrinks
While polyester is generally dimensionally stable, the actual fabric can still undergo dimensional change.
Always check the fabric before bulk production.
2. Only Checking the Fabric GSM
GSM describes fabric weight per square metre, but it doesn't give you information about fabric dimensional stability.
Always check:
GSM + DIA + Construction + Shrinkage
3. Only Checking Lengthwise Shrinkage
Widthwise shrinkage can also be an issue for garment production.
Always check both length and width shrinkage.
4. Not Testing the Fabric Sample
Don't make assumptions about fabric behaviour without testing it.
5. Not Accounting for Fabric Relaxation
Knitted fabric can behave differently after tension is released.
Always allow appropriate fabric relaxation before fabric cutting.
6. Using Different Conditions for Fabric Testing and Production
A fabric shrinkage result can vary depending on the testing conditions.
Always use the appropriate procedure for the intended application.
What to Check Before Buying Polyester Fabric in Bulk
If you're buying fabric for garment production, don't make decisions based on fabric price alone.
Ask for and confirm the following fabric specifications.
Fabric Specification Checklist
- Fabric composition
- GSM
- DIA
- Finished usable width
- Fabric construction
- Stretch and recovery
- Shrinkage
- Colour fastness
- Fabric appearance
- Hand feel
- Sample approval
- MOQ
- Bulk price
Having these specifications covered can make communication between your fabric supplier, garment manufacturer and clothing brand much easier.
Polyester Fabric Shrinkage Checklist for Bulk Buyers
Before approving a fabric for production, check the following:
☑ Fabric composition
☑ GSM
☑ DIA / finished width
☑ Fabric construction
☑ Lengthwise shrinkage
☑ Widthwise shrinkage
☑ Stretch and recovery
☑ Fabric relaxation requirements
☑ Testing conditions
☑ Sample approval
☑ Bulk fabric consistency
Using this checklist can help you avoid potential issues during garment production.
Frequently Asked Questions
Does Polyester Fabric Shrink After Washing?
Polyester generally has good dimensional stability, but the actual fabric can undergo dimensional changes depending on its construction, processing, finishing and washing.
Does 100% Polyester Fabric Shrink?
100% polyester generally has good dimensional stability, but individual fabrics can undergo dimensional changes.
Always check the actual fabric.
Does Polyester Knitted Fabric Behave Differently From Woven Polyester?
Yes. Fabric construction can influence dimensional behaviour. Knitted fabric has a looped structure and can behave differently during relaxation, processing and washing.
Should Polyester Fabric Be Tested Before Bulk Production?
Yes. Testing an approved fabric sample before bulk production can help manufacturers understand its dimensional behaviour.
Can Fabric Shrinkage Affect Garment Sizing?
Yes. Fabric length and width changes can impact garment sizing and fit.
Is GSM the Same as Shrinkage?
No. GSM describes fabric weight per square metre, while shrinkage describes fabric dimensional change after a specific process.
Is DIA the Same as Fabric Shrinkage?
No. DIA is a dimensional specification for tubular knitted fabric, while shrinkage describes dimensional changes after a specific process.
Final Takeaway
Polyester is generally dimensionally stable, but this doesn't mean that every polyester fabric will behave in exactly the same way.
Knitted construction, processing, finishing, heat treatment, relaxation and washing can all influence the dimensional behaviour of the fabric.
For clothing brands, garment manufacturers and bulk fabric buyers, checking fabric shrinkage in addition to GSM, DIA, finished width and fabric construction can help avoid issues during garment production.
The most reliable way to understand fabric shrinkage is to look at the actual fabric sample, understand its properties and test its dimensional stability before committing to bulk production.
At Walrus – Yes India Can, we supply a wide range of polyester and knitted fabrics to clothing brands, garment manufacturers and sportswear businesses from Tiruppur.
Whether you're looking for fabric for T-shirts, polo shirts, sportswear, jerseys or other apparel, choosing the right fabric specifications for your garments is an important part of developing a consistent final product.
