The Ultraviolet Protection Factor, or UPF, system measures the percentage of UV rays that will penetrate through a fabric. This diagram is very similar to the SPF one, only we are looking at the skin underneath the shirts. Again, the easiest way to calculate your protection is to multiply the UPF number by your burn time, similar to SPF burn time. In other words, as many people know, you can get sunburnt easily under an inadequate shirt fabric.

The UPF range measures from UPF 15 to UPF50+, the highest possible reading. Look for a UPF tag on garments when you purchase. And remember, not all fabrics protect. The European study we quote, shows 52% were below EU standards for sun protection.