What do the numbers mean on sunblock?

Answer by  Bob53 (414)

SPF stand for Sun Protection Factor. Sunblocks and other products that protect your skin from the sun, are given a SPF number based on how well they block against UVB rays. The higher the number, the better and longer they protect.

Answer by  drewgoldfinger (86)

SPF Stands for the Sun Protection Factor offered by the different sunscreen products. An SPF of 15 -29 provides a better shield against the damaging rays of the sun, but still lets a certain amount of penetration. SPF 30 or above offers the best sun protection.