UPF Clothing: How Sun-Protective Fabric Works (Australian Guide)
What UPF 50+ means, how fabric blocks UV, and how to choose sun-protective clothing under the Australian standard, explained by a textile engineer.
The short answer
UPF 50+ is the highest rating under the Australian and New Zealand standard for sun-protective clothing, AS/NZS 4399. A UPF 50 fabric lets through only about 1/50th of the UV that falls on it, which means it blocks around 98%. Tightly woven or knitted fabric, darker colours and polyester-based fibres give the most protection.
Australia has some of the strongest UV levels in the world, so clothing is one of the simplest forms of sun protection. Here is how it actually works, from more than 14 years of working with fabrics, dyes and finishes.
UPF vs SPF
- SPF is for sunscreen on your skin and mainly measures protection from UVB (burning rays).
- UPF (ultraviolet protection factor) is for fabric and measures protection from both UVA and UVB.
| UPF rating | Protection category (AS/NZS 4399) | UV blocked |
|---|---|---|
| 15–25 | Good | About 93–96% |
| 30–40 | Very good | About 97% |
| 50 and 50+ | Excellent | 98% or more |
What makes a fabric protective
- Tight construction. The fewer gaps between yarns, the less UV gets through. Hold a fabric up to the light: if you can see pinpricks of light, UV passes through too.
- Darker and brighter colours. Many dyes absorb UV. A navy shirt usually blocks more than the same shirt in white.
- Fibre type. Polyester absorbs UV well. Cotton, linen and viscose let more through unless they are densely woven or treated.
- UV-absorbing finishes. Some fabrics are treated with UV absorbers during finishing. These can slowly wash out, so check the care label.
- Stretch and wetness. A stretched or wet fabric often protects less, because the gaps open up. A tight wet cotton T-shirt can drop to a low UPF.
Choosing sun-protective clothing
- Look for a UPF 50+ label tested to AS/NZS 4399.
- Cover more skin: long sleeves, a collar and a longer cut protect more than any fabric rating on a singlet.
- Choose a fit that is not skin-tight, unless it is a rash guard designed for water, so the fabric does not stretch thin.
- Pick breathable fabrics for hot days: lightweight polyester knits with moisture-wicking finishes stay cooler than heavy cotton.
- Remember the rest: hat, sunglasses and sunscreen on exposed skin.
SCUBAPRO UPF 50 Long-Sleeve Rash Guard (Men's)
- UPF 50
- Long sleeve
- Polyester, made for water sports
Best for swimming, snorkelling and diving
Check price on Amazon AU Price & availability shown on Amazon.com.auFrequently asked questions
Does UPF clothing wash out?
UPF from the fabric construction and fibre does not wash out. UV-absorbing finishes can slowly reduce with many washes, so follow the care label and replace well-worn pieces.
Is a normal T-shirt enough sun protection?
A thin white cotton T-shirt can be as low as UPF 5–10, and lower when wet. A dark, tightly knitted shirt protects much better.
Is linen good for sun protection?
Loosely woven linen lets more UV through than dense polyester. It is excellent for heat (see our linen clothing guide), but add sunscreen or choose a tighter weave for long days outdoors.
What is AS/NZS 4399?
It is the Australian and New Zealand standard for testing and labelling sun-protective clothing, and it sets the UPF categories used on labels here.