Sweaters pill more than shirts because they are usually made from knitted fabrics with looser fibers.
This structure allows fibers to move, rub, and tangle more easily than the tightly woven fabrics used in most shirts.

Pilling isn’t a flaw in sweaters, it’s a natural result of how they’re built.
The short explanation (simple and true)
Sweaters pill more because:
- Knitted fabrics have looser fiber loops
- Soft yarns contain shorter fibers
- Sweaters experience more friction during wear
- Pills stay attached instead of falling off
Shirts are usually woven tighter, so fibers don’t tangle as easily.
1. Knitted fabric allows fibers to move
Most sweaters are knitted, not woven.
Knitting creates:
- Loops instead of tight crossings
- More flexibility
- More surface movement
This flexibility is what makes sweaters:
- Soft
- Stretchy
- Comfortable
It’s also what makes them more prone to pilling.
2. Sweaters use softer, shorter fibers
Sweaters often use:
- Wool
- Cotton
- Acrylic
- Blends
These fibers are chosen for softness, not stiffness.
Softer fibers:
- Break loose more easily
- Tangle faster
- Form pills sooner
Shirts often use:
- Longer fibers
- Tighter yarn twist
- Smoother surfaces
That difference alone reduces pilling significantly.
3. Friction hits sweaters harder
Sweaters experience friction in more places.
Common friction points include:
- Underarms
- Sides of the torso
- Elbows
- Areas under bags or straps
Because sweaters are bulkier and worn as outer layers, they rub against:
- Jackets
- Furniture
- Seat belts
- Bags
More friction = more pills.
4. Pills stay attached on sweaters
When pills form, what happens next matters.
On sweaters:
- Strong fibers hold pills in place
- Pills grow instead of falling off
- The surface looks fuzzier over time
On many shirts:
- Pills break off naturally
- Surface stays smoother
- Pilling is less visible
This is especially common with blended sweater fabrics.
5. Washing affects sweaters more than shirts
Washing machines affect sweaters more because:
- Knit fabrics stretch and twist
- Fibers rub more during agitation
- Heat weakens soft yarns faster
This doesn’t mean sweaters are fragile — they just need gentler care.
Related guide:
Does the washing machine cause pilling?
Does pilling mean a sweater is low quality?
No.
Some high-quality sweaters pill more than cheaper ones because:
- They prioritize softness
- They use natural fibers
- They are less tightly spun
In many cases:
- Early pilling happens
- Pills are removed
- The sweater stabilizes afterward
Can you reduce pilling on sweaters?
You can’t eliminate it completely, but you can reduce it.
Helpful habits include:
- Washing sweaters inside out
- Using gentle cycles
- Avoiding high dryer heat
- Laying sweaters flat to dry
Prevention guide:
How to prevent clothes pilling
Bottom line
Sweaters pill more than shirts because of how they’re made, not because they’re poorly made.
Knitted structure, soft fibers, and higher friction all contribute.
With the right care:
- Pilling slows down
- Sweaters stay wearable
- Fabric lasts longer