There are shelves upon shelves of sunscreens available at the store, ranging from sport to waterproof and everything in between. So how do you know if the one you’re using on yourself and your kids is the right one?

Hillary Johnson, dermatologist and professor at University of Iowa Hospitals and Clinics, said dermatologists consider a high quality sunscreen as one labeled at least 30 SPF and broad spectrum. SPF measures the protection from UVB rays that cause sunburns; sunscreens with at least an SPF of 30 provide coverage for an estimated 96 percent of the sun’s UVB rays.

Broad spectrum labels mean that the sunscreen also protects from UVA rays, which causes damage to cells like UVB rays and increases a person’s risk for skin cancers. But simply being labeled...