Use a quarter teaspoon of sunscreen on your face.

That’s about two finger-lengths of product, or roughly the size of a nickel. Yes, it sounds like a lot. It is a lot. But SPF ratings are tested at 2 mg per square centimeter of skin, and most people apply half that or less.

If you use less, you’re not getting SPF 50 — you’re getting something closer to SPF 15 or 20. The protection drops fast. There’s no magic way to cheat physics here. That quarter teaspoon is the real number.

The easiest way to get it right: don’t spread it like moisturizer. Dot it all over your face first, then blend. Or use a measuring spoon once to train your eye. After a week it’ll feel normal.

Future you with less sun damage will thank you.