UPF (Ultraviolet Protection Factor)
The number on sun-protective clothing labels: what it measures, how testing works and what counts as a good rating.
UPF, or Ultraviolet Protection Factor, is a rating that shows how well a fabric blocks the sun's ultraviolet (UV) radiation from reaching your skin. The higher the number, the less UV gets through. A fabric rated UPF 50, for example, blocks about 98 percent of the sun's rays and lets roughly one fiftieth through, as the Skin Cancer Foundation explains.
How is UPF measured?
UPF is measured in a laboratory, because only testing can show how useful a fabric is for sun protection. The test looks at how much UV, both UVB and UVA, passes through a sample of the material, and expresses the result as a rating. In Australia, ARPANSA tests garments, fabrics and hats to the national standard for sun-protective clothing, in a laboratory accredited by the National Association of Testing Authorities. Each report rates the material only. It does not evaluate the design of the garment or how much of your body it covers.
What is a good UPF rating?
UPF 50 and 50+ form the highest class. The Australian and New Zealand standard, AS/NZS 4399:2020, sorts ratings into three classes:
| Classification | UPF rating |
|---|---|
| Minimum protection | 15 |
| Good protection | 30 |
| Excellent protection | 50, 50+ |
If you work outdoors or spend long periods outside, ARPANSA advises clothing made from materials rated UPF 50.
How is UPF different from SPF?
SPF rates sunscreen, while UPF rates fabric. According to the Skin Cancer Foundation, SPF is based on how long UV-exposed skin takes to redden, and it measures only UVB. UPF accounts for both UVB and UVA.
Can a fabric's UPF change?
Yes. The label wording required by the standard warns that protection may be reduced when the material is wet or stretched, or through normal wear and exposure to chemicals. A garment also protects only the skin it covers, so ARPANSA recommends pairing clothing with a hat, sunscreen, sunglasses and shade whenever the UV index is 3 or higher. For a closer look at the top rating, read what UPF 50 means.