UPF ratings are used for fabric – SPF ratings are used for sunscreen.
Many so called sun protective fabrics look similar but not only is there is a vast spectrum of fabric quality (ie breathability, softness durability – just to name a few!) there is also a significant difference in the UPFratings which vary from UPF 15 to UPF50+.
In addition, some garments have a UV treatment applied to them after manufacture that increases the level of UPF protection but disappears after 20- 30 washes rendering them as ineffective as some cotton garments – which in some cases, only have a UPF rating of 5! Below is the Australian UPF Classification System for fabric/clothing – supplied by independent testing agent ARPANSA.