What is the difference between UPF and SPF?
The Ultraviolet Protection Factor or UPF on sun protective clothing is actually a very similar concept to the Sun Protection Factor or SPF rating for sunscreen but there are some differences. The major difference is that the UPF for sun protective clothing and swimming shirts rates protection for both UVA and UVB whereas the SPF number on sunscreen only rates protection against UVB. Also, a person wearing a UPF 30 garment will, in practice, be protected against 29 of 30 units of UVA and UVB, whereas most people who use a SPF 30 sunscreen dont apply enough sunscreen and, in practice, end up with significantly less protection, typically being protected against less than 15 of 30 units of UVB.
