UV protection in clothes and what UPF means

Short answer: UPF states how much ultraviolet light a fabric lets through. Dense and dark fabrics protect more than thin and light ones, whatever fibre they are made of.

What the number means

UPF 30 means about one thirtieth of the ultraviolet radiation passes through the fabric.

Density matters most

A densely woven or knitted fabric lets less light through. Hold the fabric up to the light and you can see the difference yourself.

Dark colours protect more

Dark dyes absorb more light than light ones. A black t-shirt protects more than a white one of the same thickness.

Wet fabric protects less

When the fabric gets wet, it lets more light through. That is worth knowing at the beach.

Clothes rather than cream on the shoulders

A layer of fabric over the shoulders is more reliable than cream that has to be reapplied. See bamboo t-shirts for men.

For hot days

A loose long-sleeved top can be cooler than direct sun on the skin. See bamboo long-sleeved t-shirt for men.

See also

More on the subject in bamboo and UV protection.

Frequently asked questions

Does an ordinary t-shirt protect against the sun?

Partly. The density and the colour decide how much, and wet fabric protects less.

Are dark clothes better than light ones in the sun?

Against radiation yes, but dark clothes get hotter to wear in direct sun.

Can clothes replace sunscreen?

Clothes cover what they cover. The rest of the skin still has to be protected.