SPF numbers, decoded

SPF 30 blocks about 97% of UVB rays, SPF 50 about 98%. The bigger difference in real life is how much you apply — most people use far less than the tested amount, so a higher SPF gives useful margin.

Mineral vs. chemical filters

Mineral (zinc oxide, titanium dioxide) sunscreens sit on top of the skin and are the gentlest choice for sensitive or acne-prone skin, but can leave a white cast on deeper skin tones. Modern chemical filters are lighter, blend invisibly and suit everyday wear under makeup.

Look for "broad spectrum"

UVB causes burning, UVA causes long-term photoaging. A broad-spectrum label means the formula protects against both — this matters more than the SPF number itself.

Finish and skin type

Gel and fluid textures suit oily skin; cream textures suit dry skin. If a sunscreen makes you look greasy by noon, a "matte finish" or "no sebum" formula will keep you wearing it daily.

Reapplication in the real world

For office days, applying a full layer in the morning is a realistic baseline. For beach days or long time outdoors, reapply every two hours — SPF sticks and sprays make touch-ups over makeup easier.