Does Doubling Sunscreen SPF Double Protection

Does a very high SPF on a sunscreen give much more protection than a lower SPF? For instance, is a 60 twice as protective as a 30? The answer is no. SPF means “sun protection factor” which tells you how long you can be in the sun without getting a burn, but the relationship between SPFs and the amount of protection you get is not linear. So, in fact, when you double SPF from 15 to 30, you go from 88% protection from the burning rays to 95% protection, an increase in 7%, from doubling from 15 to 30, but double again from 30 to 60, and you only get 4% more protection, from 95 to 99. So, using higher and higher SPFs is not necessarily going to give you a tremendously greater amount of protection from the sun. It’s better to use an SPF between 15 and 30, which is in a liquid that feels good when it goes on your skin, so you’ll re-apply it frequently than to use a very, very high SPF.