Between UPF and SPF (or SPF), the concept is essentially the same, protecting your skin from ultraviolet rays.
UPF is to fabrics and clothing, what SPF is to creams, lotions and serums.
UPF corresponds to tests carried out by spectrophotometer on a tissue. The UPF 25 index means that the fabric lets through 1/25 of UVA and UVB radiation. A UPF 50+ garment (maximum protection) will block at least 98% of UVA and UVB rays (only 2% of UVA and UVB rays pass through).
SPF only measures the protection of the sunscreen against UVB rays, the scorching rays. When applied correctly, SPF 50 blocks 98% of UVB rays. The SPF index indicates the time that a person can expose themselves before being burned For example:SPF 25 means that if it takes 10 minutes to have a naked sunburn, with a sunscreen 25, it is necessary count 250 minutes.