What Does Sunscreen SPF Really Mean?

The easiest way to know how long you can stay in the sun without getting burned.

Science What Does Sunscreen SPF Really Mean? SPF (Sun Protection Factor) is a multiplication factor you can use to determine how long you can stay out in the sun before getting a sunburn. Here's how to calculate it for yourself. READ NOW Advertisement READ THESE When Does Summer Actually Start? The Top 10 Summer Songs of All Time 10 Steven Spielberg Movies You Need to See This Summer You are receiving this newsletter because you subscribed to the Today I Learned newsletter. If you wish to unsubscribe, please click here A Dotdash Brand 1500 Broadway, 6th Floor, New York, NY, 10036 © 2017 Dotdash - All rights reserved. Privacy Policy.