What a fibre content of 95 and 5 means

Short answer: The numbers are the weight percentage of each fibre in the fabric. Ninety five percent viscose and five percent elastane mean the fabric is soft and can also stretch and recover. The main fibre gives the feel, and the small share holds the shape.

What the percentages on the label tell you

When a care label says 95 and 5, it shows how the fibres are split by weight. The number does not say how much space each fibre takes up, but how many grams of each material the fabric contains. That makes comparison easy, because every maker has to state fibre content the same way.

The main fibre decides the feel

The ninety five percent decides how the fabric feels on the skin, how it takes up moisture and how it ages. It is the viscose you notice when you pull on bamboo socks in the morning. It gives the smooth, cool surface and soft drape many people link with bamboo clothing.

The five percent does the work

Elastane weighs little, but it sits in every single stitch and pulls the fabric back into shape after it has been stretched. Without it, a bamboo bra would sag after an hour and lose the support it is meant to give. The small share is key to the fit, even if it is rarely mentioned.

Why not more elastane

More elastane gives more stretch, but also less breathability and a shorter life, because elastane breaks down before viscose. Five percent is a well tested balance between softness and shape. You can see it in a bamboo hoodie for women, where the fabric should stay soft and keep its shape at cuffs and hem.

Weight and volume are not the same

Because the percentages are measured by weight, elastane can take up more room in the fabric than the number suggests. Elastane is a light fibre, so five percent by weight equals a larger share of the yarns. That is one reason the fabric stretches so well even though most of it is viscose.

How to read a label

Look first at the main fibre, because it tells you how the garment will feel. Then look at the share of elastane. If it is low, the garment sits looser and softer. If it is higher, it sits closer and firmer. Compare two garments of the same type to see the difference before you choose.

How to protect the small share

Elastane does not like heat, so it is the part of the fabric that needs the most care. Wash at a low temperature, skip the tumble dryer and let the garment dry flat or on a hanger. That way the elastane lasts longer and the garment keeps its shape. Viscose handles the same care well.

When the elastane is worn out

After long use the elastane can be broken down, even if the fabric still looks whole. You notice it when waistbands turn slack and the garment no longer pulls back after washing. That is a sign it has done its job. The viscose is still soft, but the shape is not what it was.

Frequently asked questions

Are the percentages measured by weight or volume

By weight. Elastane is a light fibre, so it takes up more volume than the five percent suggests, which is why the fabric stretches so well.

What happens when the elastane has broken down

The fabric stays whole, but it no longer returns to shape, and waistbands and edges gradually become slacker than before.

Are there basics without elastane

Yes, but they sit looser and lose their shape faster in use, because the knit only slowly and partly recovers after stretching.