Why Your Sweaters Pill and How to Stop It Happening

Quick answer

Sweaters pill because short or loose fibers work their way out of the yarn and tangle into little balls under friction from wear, washing, and rubbing against bags or seatbelts. You can stop most of it by washing knits inside out on cold and air-drying flat, giving them a rest day between wears, and removing existing pills with a fabric shaver or sweater comb instead of pulling them off.

What actually causes pills on a sweater

A pill is a tangle of fibers that has migrated out of the yarn and knotted on the surface. Two things have to happen: fibers must be loose enough to escape the twist, and friction must rub them together. That is why pills show up first under the arms, along the sides where a tote bag sits, and anywhere a seatbelt or jacket strap drags across the knit.

Fiber blend matters more than price. Softer, finer fibers tend to be shorter and slip out more easily, while longer, smoother fibers hold their place. Blends are not automatically worse; they simply behave differently. A yarn with a small percentage of a fluffy fiber can feel luxurious but will need gentler handling than a tight cotton knit.

How to stop sweater pilling before it starts

The single most effective habit is to give a sweater a recovery day. Knit fibers stretch while you wear them and need roughly 24 hours to spring back, so rotating between two or three sweaters reduces the constant abrasion that creates pills. When you take a sweater off, fold it rather than hanging it; hangers stretch shoulders and cause the knit to rub against itself on the rail.

Washing is the other big lever. Turn the sweater inside out, use a mesh laundry bag, choose the cold delicate cycle with a low spin, and use a gentle detergent without bleach or fabric softener. Softener coats fibers and makes them more likely to slip, which is the opposite of what you want. Never put a sweater in the dryer; heat and tumbling are a pill factory. Instead, press the water out in a towel, reshape the sweater, and dry it flat away from direct sun.

How to remove pills from a sweater safely

Once pills form, remove them rather than picking them off with your fingers. Pulling a pill tugs more fibers loose and can leave a thin spot. Lay the sweater flat on a hard surface, smooth the area, and run a fabric shaver in short, light strokes with the grain of the knit. Empty the shaver often so it keeps cutting instead of dragging.

If you do not own a shaver, a fine-tooth sweater comb or a clean, dull razor used at a shallow angle works for small areas. Work in daylight, stop when the surface looks even, and avoid pressing hard on ribs, cables, or raised stitch patterns because you can catch the texture itself. For a cable knit, shave around the cables rather than across them.

When pilling means the sweater needs a different approach

Some pilling is normal and will slow down after the first few wears as the loose surface fibers work free. If pills keep returning in the same spot within a week, the friction source is the problem, not the sweater. Check whether a bag strap, a rough jacket lining, or a tight coat is rubbing the same area and change how you layer.

If the knit feels thin, see-through, or fuzzy all over rather than in isolated spots, the fibers are breaking down rather than simply migrating. At that point shaving will not restore it, and the sweater is better suited to lounging than to daily wear. Stop shaving and either repurpose it or replace it with a tighter, smoother knit.

Diagnose your pilling before you treat it

• Symptom: Small, scattered balls of fiber on the underarms, sides, or wherever a bag or strap rests, with the rest of the knit still smooth. This is normal friction pilling and is safe to remove with a fabric shaver.
• Likely cause: Repeated rubbing from outer layers, bags, or seatbelts combined with short, loose fibers in the yarn blend. Change the friction source before you change the sweater.
• Corrective action: Wash inside out on cold delicate, dry flat, rest the sweater a day between wears, and shave pills in short light strokes with the grain. Consistent care slows new pills far more than any single treatment.
• Stop point: If the knit is thin, see-through, or fuzzy all over, or if pills return in the same spot within a week, shaving will not fix it. Repurpose the sweater for low-friction wear or choose a tighter, smoother knit instead.

How two knits from our range handle friction differently

• Alina Sweater: Cable knit with ribbed trim, made from 13% de-haired angora, 47% acrylic, and 40% polyamide, with a 29-inch length and 23.5-inch bust. The raised cable and rib texture creates more surface contact points, so shave around the cables rather than across them and expect the trim to be the first place pills appear.
• Coco Knit Top: Long sleeve wrap top with a deep V-neckline, crossover front, self-tie back, and side opening, in 13.6% mohair, 39.0% acrylic, and 30.6% polyamide, with a 16-inch length and 16-inch bust. The wrap ties and crossover front rub against each other and against outer layers, so fasten the self-tie loosely and avoid rough tote straps across the front to reduce friction pilling.