What Does UPF Mean?

Have you ever seen a pair of hiking pants or a lightweight technical shirt with a mysterious UPF rating? What does this rating mean, and why is it important? UPF ratings indicate sun protection, which is something that anyone who spends time outdoors should care about.

What is UPF?

UPF stands for ultraviolet protection factor. The sun emits UV radiation which can cause sunburn and skin cancer. A UPF rating indicates the level of protection from ultraviolet radiation that a garment provides.

For example, a shirt with a UPF 50+ rating blocks roughly 1 unit of UV radiation per 50 units. This means that 49 out of 50 units of UV radiation are blocked by the shirt. In other words, sun protective clothing with an ultraviolet protective factor of 50 blocks 98% of UV radiation that falls on the fabric.

SPF and UPF are two different things

While SPF and UPF basically do the same job – that is, keep you safe from the sun – there is a difference between the two.

The main difference between UPF and SPF is that SPF is exclusive to sunscreen and UPF is exclusive to fabrics.

Another key difference between SPF and UPF is that UPF ratings measure how well a fabric blocks radiation, whereas SPF measurements typically focus on sunburn rather than radiation.

UPF fabrics have built in sun protection, whereas the protection from SPF sunscreen wears off over time. Sun protective clothing has the edge over sunscreen because of the passive protection from UV radiation.

Why is UPF clothing important?

It’s important to keep your skin safe from the sun, especially if you’re sensitive to sunlight or outside for long periods of time. Sun protective clothing with a UPF rating can help you stay safe.

All clothing provides at least some level of sun protection. However, your average t-shirt and blue jeans don’t advertise a UPF factor because they typically don’t offer much protection from UV radiation.

Outdoor apparel, especially hiking pants and hiking shirts, often come with a UPF rating. Anything with a UPF rating of 30 or more is considered sun protective clothing.


We carry a great selection of outdoor apparel and sun protective clothing from great brands like Outdoor Research that will keep you safe on your next hike or day on the lake or river. Stop by and see us at Uncle Sam’s Safari Outfitters in Fayetteville, Arkansas!

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