What is UPF?

Posted by Cris Herrera on

UPF stands for Ultraviolet Protection Factor and is a rating system used to show how effectively fabrics shield skin from ultraviolet (UV) rays. The higher the UPF rating, the greater degree of UV protection a garment offers. 

A fabric with a rating of UPF50 is considered among the highest protection rating, blocking 97.5% of UV radiation exposure to the skin, making it one of the safest and easiest ways to protect your skin from damage.


One common misconception about UPF is that it is a treatment that is applied to the fabric after it's been weaved. On the contrary, the UPF rating system considers the construction of the fabric from the density of the weave, yarn gauge and fiber structure. Other factors to consider include fabric color, weight and stretch. 


The UPF rating system was developed in 1998 by Committee RA106 using AATCC Test Method 183¹. This method is based on the original guidelines established in Australia in 1994.

The main difference between UPF rating system and the SPF rating system is that SPF only tests for UBV rays, where UPF tests for both UBV and UVA rays.

Below is the ASTM (American Society for Testing and Materials) Standard for Sun Protective Clothing:

UPF rating Protection category % UV radiation blocked
UPF 15–24 Good 93.3–95.9
UPF 25–39 Very good 96.0–97.4
UPF 40–50+ Excellent 97.5–98+



Below are some fabrics we offer that hold exceptional sun protection properties. Many of them also have a ChitoSanté treatment, which is an environmentally friendly treatment that adds anti-bacterial, non-toxic, breathable, anti-static and moisture wicking features.

UPF Fabric Listing: 


Read more on UPF and it's skin protection properties below.

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The KenDor Resources and Useful Links are intended to aid our customers in understanding the general guidelines and/or industry standards for certain practices or fabric characteristics.  These resources are not to be considered an official resource of information and should not be referenced as formal or legal standard guides.  Customers are responsible for all fabric testing, securing marketing licenses and any claims made for their individual products.  KenDor is not liable for any customer claims made.

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