4 Things to Know About SPF 30 vs SPF 50

SPF measures UVB ray blockage, not protection time. SPF 30 blocks about 97% of UVB rays, while SPF 50 blocks about 98%.

The extra 1% matters if you burn easily or spend hours in direct sun. For most people, SPF 30 is enough if you reapply.

Most people don’t apply enough sunscreen to get the labeled protection. You need about a shot glass full for your body, but most people use half that.

The practical difference between SPF 30 and 50 shrinks even more with poor application. Wear whichever one you’ll actually apply and reapply.