How is UPF Different from SPF?

UPF (Ultraviolet Protection Factor) and SPF (Sun Protection Factor) both measure sun protection, but they apply to different things. UPF refers to how much UV radiation a fabric allows to reach your skin, while SPF measures how long sunscreen protects skin from UVB rays. In short: UPF is for clothing, SPF is for sunscreen.

Understanding the Difference:

• UPF (Ultraviolet Protection Factor) is used for fabrics. A UPF 50 rating, for example, means that only 1/50th (or 2%) of UV rays can penetrate the fabric, blocking 98% of them. UPF covers both UVA and UVB rays.
• SPF (Sun Protection Factor) is used for topical sunscreens. SPF only measures protection against UVB rays, which cause sunburn. An SPF 30 sunscreen, for example, blocks about 97% of UVB rays for a set amount of time depending on your skin type and sun intensity.

Why the Difference Matters:

Many people think sunscreen alone is enough—but it often isn't. Sunscreen can wear off with sweat or swimming and needs frequent reapplication. UPF clothing, on the other hand, offers consistent and passive protection that doesn't wash or rub off during wear (if the fabric and construction are high quality).

Also, UPF-rated garments shield both UVA and UVB rays, while many sunscreens protect only UVB unless labeled "broad spectrum."

Scientific Backing

• The Skin Cancer Foundation recommends UPF clothing as a reliable and necessary form of sun protection, particularly during long periods outdoors (Skin Cancer Foundation).
• According to the CDC, clothing is the first line of defense against UV exposure (CDC).
• The American Academy of Dermatology supports UPF clothing as part of a complete sun safety routine (AAD).

Summary

While SPF helps protect your skin with lotions and creams, UPF blocks UV rays through fabric. Together, they can be a powerful combination—but if you want all-day, low-maintenance protection, UPF clothing is a smart choice.

Some Sun creates stylish, elevated UPF 50+ clothing for women who want to protect their skin without compromising on style. Unlike sporty or overly casual options, our pieces are made to blend seamlessly into everyday wardrobes, so you can wear them on walks, errands, beach days, or even brunch.

Discover your new favorite sun protection staples. Shop the UPF collection at Some Sun now.