A sunscreen’s sun protection factor (SPF) tells you how long your protection can last outdoors before having to reapply. The sun can be harmful due to ultraviolet B (UVB) ray exposure, so the SPF component measures the level of UVB protection a sunscreen offers.
SPF stands for Sun Protection Factor. Every skin type has a different length of time until it burns in the sun. SPF 15 extends that time by 15, SPF 30 extends that time by 30 and SPF 50+ extends that time by at least 50 times. There are however multiple factors that also affect your level of protection, such as how much sunscreen you apply, the weather and if you have been sweating or swimming. If you’re going to be out in the sun for an extended amount of time, don’t forget to cover up with sun protective clothing such as shirts, wide brimmed hats and sunglasses, apply sunscreen with an SPF50+ rating and reapply regularly.