Short answer: the composition tag is the more useful of the two labels, because the care symbols tell you what the manufacturer will defend and the composition tells you what the garment actually is. Read it in order of percentage: the first fibre sets the character, and anything from 2 to 10 percent elastane sets the washing rules regardless of what comes before it. Heat is the enemy of elastane, and elastane is in most of your wardrobe.
The fibres, and what each one does
| Fibre | Behaves like | Wash | Watch for |
|---|---|---|---|
| Cotton | Absorbent, strong wet, forgiving | Cold to 60 °C by use | Shrinks hot, creases, greys if washed too cool |
| Linen | Very strong, cool, creases by nature | Cold to 40 °C | Softens with every wash; the creasing is the point |
| Wool and merino | Warm, odour-resistant, recovers with rest | Cool wool cycle or hand | Felts with warmth plus agitation. Never tumble |
| Cashmere | As wool but finer and weaker | Cool hand wash | Pills early if the staple is short |
| Silk | Strong but chemically fussy | Cool, brief, no bleach | Spots with water, dulls with residue |
| Polyester | Tough, holds shape, holds odour | Cold to 40 °C | Traps body oil, which is why it smells. Melts above about 60 °C |
| Nylon or polyamide | Very strong, elastic, light | Cold | Yellows with age and heat |
| Acrylic | Wool-like and cheap | Cold, gentle | Pills badly and permanently |
| Elastane, Lycra, spandex | Stretch and recovery | Cold, air dry | Destroyed by heat and chlorine. This is the one that matters |
| Viscose, rayon, modal | Drapes like silk, made from cellulose | Cool, support the weight | Loses most of its strength when wet. Shrinks on first wetting |
| Lyocell or Tencel | Viscose done better | Cool | Stronger wet than viscose, still not cotton |
| Acetate | Shiny, used for linings | Cool or dry clean | Dissolves in acetone. Keep nail varnish remover away |
How to read a blend
Percentages are listed highest first, and the practical reading is simple: the first fibre gives the character, the last fibre gives the rules.
- 95% cotton, 5% elastane. A cotton T-shirt that behaves like cotton and must be washed and dried like elastane. Cold, no dryer. This is the most common tag in most wardrobes.
- 60% cotton, 40% polyester. School uniform and workwear. Less creasing, more odour retention, needs a full dose and no softener.
- 70% wool, 30% polyamide. A sock or a hard-wearing knit. The nylon is there for strength at the heel and cuff; still a cool wash.
- 100% viscose. Looks like silk, costs like cotton, and loses its strength the moment it is wet. Handle it as the most fragile thing in the load.
- 88% polyester, 12% elastane. Activewear. Cold, full dose, extra rinse, no softener ever, never a dryer.
- 100% cotton with no elastane. The forgiving case. You can wash it warm and tumble it, within reason.
- Anything with 2% or more elastane, whatever the rest says, goes cold and air dries. One line on the tag overrides the others.
Composition versus the care symbols
The care label lists one method the manufacturer is prepared to stand behind, which is often the most cautious one rather than the only safe one. The composition tag is a statement of fact. When the two seem to disagree, the composition usually tells you what is really going on: a "dry clean only" label on 100% merino is caution, and the same label on a lined wool jacket is physics. The symbol side of it is covered in laundry symbols explained, and where the label can be ignored in dry clean only.
Buying better, in thirty seconds
- Check the elastane first. It determines how the garment must be washed for its whole life, and it is what fails first.
- Prefer single fibres where you can. Blends pair a shedding fibre with one that holds on, which is why they pill. See why clothes pill.
- Look for long-staple descriptions on cotton and cashmere. That phrase is most of the price difference between a jumper that lasts and one that does not.
- Rub the fabric between your palms for ten seconds. If pills appear in the shop, they will appear in week two.
- Hold a knit to the light. If you can see through it easily, it will bobble and lose shape.
- Check the lining separately. A wool coat with an acetate lining is a dry clean garment because of the lining, not the wool.
- Weight tells you a lot. Two shirts of the same composition can be very different garments; the heavier one usually lasts.
Common problems traced back to the tag
| Problem | The tag said | What happened |
|---|---|---|
| Jeans went baggy at the knee | Elastane in the blend | Elastane fatigue between washes. Cold wash and line dry restores most of it |
| Waistband permanently slack | Elastane | Cooked in a hot dryer. Not reversible |
| Gym top smells straight out of the wash | High polyester | Polyester holds the oil odour bacteria feed on. Vinegar pre-soak, full dose, no softener |
| Dress two sizes shorter | 100% viscose | Viscose shrinks on first wetting, permanently. Steam and pull back while damp |
| Jumper felted and dense | Wool | Warmth plus agitation. Conditioner soak recovers some |
| Cheap knit bobbled all over | Acrylic | Acrylic pills permanently because the fibre is strong enough to hold the pill |
| Lining puckered, outer fine | Two different fibres | They shrank at different rates. A tailor can sometimes re-hang the lining |
| White nylon gone yellow | Nylon | Age and heat. Oxygen bleach helps a little; mostly permanent |
Frequently asked questions
How do you read a fabric composition label?
Percentages are listed highest first. The first fibre gives the garment its character — how it feels, drapes and breathes — and the smallest fibre usually sets the washing rules. Anything with 2 percent or more elastane must be washed cold and air dried regardless of what the rest of the blend says.
Why does a small amount of elastane matter so much?
Because elastane is destroyed by heat and chlorine, and it is the component that fails first. A 95 percent cotton T-shirt with 5 percent elastane behaves like cotton to wear but must be treated like elastane to wash: cold water and no tumble dryer, or the fit goes permanently.
What is the difference between viscose, rayon, modal and lyocell?
They are all made from cellulose and drape like silk. Viscose and rayon are the same thing under different names and lose most of their strength when wet. Modal is stronger, and lyocell or Tencel is stronger still. Treat plain viscose as the most fragile item in any load.
Is the composition label more useful than the care symbols?
Usually, yes. The care label lists one method the manufacturer is prepared to defend, which is often the most cautious rather than the only safe one. The composition tag is a statement of fact about what the garment is, so it tells you what the fabric can actually take.
Why do blended fabrics pill more?
Because a blend typically pairs a fibre that sheds short ends with a stronger fibre that holds them. On pure cotton a pill breaks off and disappears; on a cotton-polyester blend the polyester anchors it, so the pill stays. Single-fibre garments generally pill less.
What does 100% cotton really mean for washing?
That it is the forgiving case. Cotton is strong when wet, tolerates warm water and can be tumble dried within reason, though heat shrinks it and washing too cool leaves body oil behind, which is what greys white collars. The absence of elastane is what gives you the latitude.
Should I avoid synthetic fabrics?
Not necessarily. Polyester and nylon are durable, hold their shape and often outlast natural fibres, and a synthetic garment worn two hundred times beats a cotton one worn twice on every measure. They do hold odour more and shed microfibres, so wash them cold, full, and less often.
