"To actually achieve the SPF that the sunscreen promises, you should be applying approximately two milligrams of sunscreen per square of skin. That's the equivalent of about two tablespoons for the body," says Dr. Alexis Granite. "For the face, I like to use the two-finger rule—the amount to cover the face and neck should be equal to the lengths of your second and third fingers. Make it the last step in your daily skincare routine and don’t forget to cover the ears and neck, too!
"If you’re using a chemical sunscreen, you need to apply it 30 minutes before going outdoors to ensure it’s properly absorbed into the skin," she adds.