UPF vs. SPF: Decoding the Number on Your Sun Shirt
SPF rates your lotion; UPF rates your shirt, and understanding the difference tells you why a good garment can outwork sunscreen all day.
Per AAD criteria, a UPF 50+ garment lets through only about 1/50th (roughly 2%) of UV rays and blocks both UVA and UVB without any reapplication.
MD Anderson experts explain that UPF reflects how much UV a fabric blocks across the spectrum, making it the clothing-world counterpart to SPF on a sunscreen label.
Questions we get a lot
What is the difference between UPF and SPF?
SPF (Sun Protection Factor) rates how well a sunscreen filters UVB radiation, while UPF (Ultraviolet Protection Factor) rates how much total UV a fabric blocks. UPF accounts for both UVA and UVB, whereas SPF testing centers on UVB. In short, SPF is for what you rub on and UPF is for what you wear.
How much UV does a UPF 50+ garment block?
A UPF 50+ garment lets through only about 1/50th, or roughly 2%, of UV rays, blocking the rest. It protects against both UVA and UVB and never needs reapplication. That consistency is why a quality sun shirt can outperform sunscreen over a full day outdoors.
r/SkincareAddiction: 'My rash guard says UPF 50, is that the same as SPF 50 sunscreen?'