Clothes shrink when heat, water and movement act on natural fibres, so the fix is to reduce all three. Wash cotton, linen and viscose at 30°C or below on a gentle cycle with a lower spin, put wool on a wool or hand-wash setting, and avoid the tumble dryer for anything prone to shrinking. Most shrinkage actually happens in the dryer, not the washing machine, so air drying is the single biggest change you can make.
A jumper that comes out two sizes smaller is rarely bad luck. Each fibre shrinks for a different reason, and once you know which one you are dealing with, choosing the right settings becomes simple. This guide is part of our wider advice on getting laundry fresh and clean in the UK.
Why Clothes Shrink: It Depends on the Fibre
Shrinking is not one process. Cotton and wool, the two biggest culprits, shrink in completely different ways.
| Fibre | Shrink risk | What happens | Safest approach |
|---|---|---|---|
| Cotton | Medium to high | Fibres stretched during manufacture relax back when wet and hot, especially in the first few washes | 30°C, lower spin, air dry |
| Wool and cashmere | High | Tiny scales on each fibre lock together under heat and friction (felting), which is permanent | Wool cycle or hand wash, cool water, dry flat |
| Linen | Medium | Like cotton, it tightens with heat, mainly on the first wash | Cool wash, line dry while slightly damp |
| Viscose (rayon) | High | Weak when wet, so it distorts and shrinks easily | Follow the label; often hand wash cold or dry clean |
| Polyester and nylon | Low | Rarely shrink, but high heat can warp or melt them | Cool to warm wash, low-heat dry |
Blends behave like their most delicate fibre. A cotton and elastane top, for example, needs gentler drying than plain cotton because heat also weakens the stretch.
Washing Settings That Prevent Shrinking
- Read the care label first. The number in the washtub symbol is the maximum temperature, not a recommendation to use it.
- Choose 30°C or lower for cotton, linen and anything you are unsure about. Modern detergents clean well at low temperatures.
- Use a gentle or synthetics cycle for shrink-prone items, as they use less drum movement than a standard cotton cycle.
- Lower the spin speed to around 800 rpm for knits and delicates to reduce friction and stretching.
- Do not overload the drum. Packed clothes rub together more, which speeds up felting in wool.
- Keep wool separate and use a wool cycle with a detergent made for wool. Our guide to the best wool wash liquid explains why ordinary bio detergent damages wool fibres.
Drying: Where Most Shrinking Really Happens
Many people blame the washing machine, but the tumble dryer combines all three shrinking triggers at once: heat, moisture and constant movement. If you only change one habit, change how you dry.
Air Dry Shrink-Prone Items
Hang cotton and linen on a line or airer. Shake each item and smooth the seams before hanging.
Dry Knits Flat
Wool, cashmere and heavy knits stretch out of shape on a hanger. Lay them flat on a towel and reshape by hand.
Use Low Heat If You Must Tumble
Choose the low heat setting and take clothes out while very slightly damp, then let them finish drying in the air.
Keep Away From Radiators
Direct, intense heat on a damp garment can shrink and stiffen it, as well as adding moisture to the room.
The Care Label Symbols That Matter
| Symbol | Meaning |
|---|---|
| Washtub with a number (30, 40, 60) | Maximum wash temperature in °C |
| One bar under the washtub | Gentle cycle with reduced spin |
| Two bars under the washtub | Very gentle cycle, usually for wool |
| Hand in the washtub | Hand wash only |
| Square with a circle inside | Can be tumble dried; one dot means low heat, two dots normal heat |
| Any symbol crossed out | Do not do this |
The Home Laundering Consultative Council sets out the full UK care labelling system if you come across a symbol that is not listed here.
Can You Unshrink Clothes?
Sometimes, partly. Soaking the garment for about 30 minutes in lukewarm water with a little hair conditioner or baby shampoo relaxes the fibres, after which you can gently ease it back into shape and dry it flat. This works best on cotton and knits that have tightened slightly.
Know the Limits
Felted wool cannot be reversed, because the fibres have physically locked together. Stretching too hard can also tear seams or leave a garment misshapen. Treat any rescue attempt as a bonus rather than a guaranteed fix, and never put a stretched item in the dryer to "set" it. For wool specifically, The Woolmark Company publishes detailed care advice.
Buying Clothes That Shrink Less
- Look for "pre-shrunk" on cotton labels. The fabric has already been through a controlled shrinking process.
- Check the fibre mix. Cotton blended with polyester usually shrinks less than 100% cotton.
- Allow a little room in 100% cotton that is not pre-shrunk, as it can tighten slightly over the first few washes.
- Look for machine-washable wool if you want knitwear you can put in the machine on a wool cycle.
Shop Laundry Care
Detergents, fabric care and laundry essentials for clothes that keep their size and shape.
Shop Laundry CareFrequently Asked Questions
Does washing at 30°C stop clothes shrinking?
It greatly reduces the risk for cotton and linen, but drying matters just as much. A 30°C wash followed by a hot tumble dry can still shrink clothes.
Do clothes shrink more in the washer or the dryer?
Usually the dryer. It combines heat, moisture and movement for a long time, which is exactly what makes cotton relax and wool felt.
Does cotton keep shrinking every wash?
Most cotton shrinkage happens in the first few washes. After that, garments usually stay stable if you keep washing and drying them the same way.
Why did my polyester top shrink?
Pure polyester rarely shrinks, so check the label for cotton or viscose in the blend. Very high heat can also warp synthetic fibres.
Sources: Home Laundering Consultative Council, UK care labelling; The Woolmark Company, wool care guidance; Which?, washing machine temperature guide.