Worried your favourite jumper will come out doll-sized? Here is how to wash wool sweaters safely: use cool water, a wool-safe detergent, gentle pressing, and lay the sweater flat to dry.
This guide is part of our wider series on how to care for clothes.
| Item | Value |
|---|---|
| Hand-wash water temperature (care-label guidance) | Between 30°C and a maximum of 40°C, depending on the article |
| Machine-washable wool label | 40°C (or 30°C) very mild wash |
| Hand-wash soak time | About ten minutes |
| Bleach | Not allowed when the label shows the crossed triangle |
| Drying | Lay flat on a rack, not in the dryer |
These figures come from Woolmark’s care-symbol guide and a retailer’s hand-wash guide. Guidance can change, so check the sources and your garment’s own label before you rely on them.
Why wool shrinks in the first place
Wool fibres tangle together when they are wet, warm and moved around. That tangling is called felting, and it is what turns a roomy sweater into a small, stiff one.
The dryer is the main culprit. In the words of one style guide, “where felting occurs most often is in the dryer as the clothes are dry, hot, and being constantly agitated.”
So the aim is simple: keep heat, friction and twisting low at every stage. The rest of this guide follows from that.
Do you need to wash it at all?
Often less than you think. One guide notes that wool contains lanolin oils that make it naturally anti-microbial, so an airing between wears can replace many washes.
Air the sweater near an open window or on a rack between wears. Spot-clean small marks rather than soaking the whole garment.
Washing less is also kinder to a sustainable wardrobe, since every wash is a chance for something to go wrong.
Read the care label first
The label tells you which care method to follow. Woolmark’s guide explains that many wool items can go in the washing machine, but not all.
- Hand wash symbol: follow the garment’s specified hand-washing temperature within the 30–40°C range.
- Machine-washable wool: the label reads “40°C (or 30°C) very mild wash”.
- Do not bleach: a crossed triangle means bleaching is not allowed, so use only bleach-free detergent.
- Do not tumble dry: the garment must not go in a dryer.
If the label is missing or faded, check the maker’s care instructions before washing. Blends with delicate fibres such as cashmere deserve the same caution.
How to hand wash a wool sweater
If the care instructions permit hand washing, allow about ten minutes for soaking, plus time for rinsing and drying.
- Use cool water and a detergent suitable for wool, measuring the dose according to the detergent label.
- Submerge the sweater and let it soak for about ten minutes.
- Press it gently against the side of the basin. Do not scrub or rub.
- Drain the water and refill with clean water of the same temperature to rinse.
- Repeat the rinse until the water runs clear of suds.
Never wring it out. One guide warns that wringing means “excessive agitation” that will distort the fibres and might cause some felting.
Machine washing, if the label allows it
Woolmark notes that many pieces of wool clothing can actually be put in the washing machine. Use that only when the label permits it.
A retailer guide lists the settings to choose if you do machine wash a wool piece:
- Cold water
- A wool or delicate cycle
- A mesh laundry bag
- Wool-safe detergent
- The lowest spin
Skip bleach, which the Do Not Bleach symbol rules out on many labels. If your knitwear already has bobbles, see our guide on how to prevent clothes from pilling.
Drying and reshaping without damage
Drying is where many sweaters are ruined, so go slowly. Take the sweater out of the water without lifting it by the sleeves, because wet wool is heavy.
- Lay a clean towel flat and place the sweater on it in its natural shape.
- Gently roll the sweater inside the towel so the towel absorbs excess water.
- Unroll the towel and move the sweater to a drying rack.
- Smooth the body and sleeves back to their original size while still damp.
Do not hang a wet sweater. Hanging can stretch the shoulders and distort its shape, and a dryer risks felting.
Fold wool for storage rather than hanging it. If a seam or moth hole turns up while you handle it, our guide on how to mend clothes shows you how to repair it before it spreads.
Common mistakes that cause shrinking
Most ruined sweaters come down to a handful of habits. Check this list before your next wash.
- Using the dryer. Heat, dryness and constant tumbling are the combination that felts wool.
- Wringing or twisting. Squeeze water out by rolling the sweater in a towel instead.
- Hanging it wet. The weight of the water pulls the shoulders and body out of shape.
- Skipping the label. A wool blend may tolerate less than pure wool, so the label always comes first.
- Using bleach. Where the label shows the crossed triangle, bleaching is not allowed.
Use a cool hand wash and flat drying when the sweater’s care instructions permit them.
A simple routine you can repeat
Build a short habit around your knitwear and you will rarely face a rescue job. It takes very little effort once it becomes automatic.
- Wear the sweater, then air it out before folding it away.
- Spot-clean small marks with a damp cloth when you can.
- Wash only when it is truly dirty, following the label.
- Press gently, never wring, and rinse in water of the same temperature.
- Roll in a towel, reshape, and dry flat.
- Fold it for storage rather than hanging it.
This approach keeps a good sweater in use for many winters. It is also cheaper and lower-impact than replacing shrunken knitwear.
Frequently asked questions
Can I use normal laundry detergent on wool?
Show answer
Use a wool-safe detergent instead. Woolmark’s symbol guide says to use bleach-free detergent where bleaching is not allowed, and wool-specific products are made for this fibre.
Is cold or warm water better?
Show answer
Cool water is the cautious choice for hand washing. Woolmark’s hand-wash symbol allows between 30°C and a maximum of 40°C depending on the article, so start at the cooler end.
Can I tumble dry a wool sweater?
Show answer
Only if its label says so. Woolmark’s guide says clothes marked Do Not Tumble Dry must not be placed in a dryer, and flat drying is the safer default.
Can I fix a sweater that has already shrunk?
Show answer
Felting tangles the fibres, so prevention is far easier than repair. Gentle reshaping while the wool is still damp is the best step you can take.
