How to Choose a Sunscreen | Picks That Actually Protect

Choose a broad-spectrum sunscreen with SPF 30 or higher and water resistance if you’ll swim or sweat — that combination covers UVA and UVB rays.

Picking a sunscreen feels harder than it should be. The difference between a good choice and a wasted purchase comes down to three lines of fine print. The right routine starts with reading a label the way the FDA actually writes it. Here is the short version of what dermatologists want you to check, plus the mistakes that quietly undermine most people’s protection.

The Three Label Checks That Matter Most

Every sunscreen you buy should pass three quick checks before it goes in your cart.

First, the label must say broad spectrum. That phrase is regulated by the FDA — a product can only carry it after passing specific tests proving protection against both UVA and UVB rays. UVB causes sunburn; UVA contributes to skin aging and cancer risk. Without broad-spectrum coverage, high SPF numbers only tell half the story.

Second, choose SPF 30 or higher. The American Academy of Dermatology (AAD) recommends SPF 30+ for routine daily use. The FDA notes that SPF 15 is the minimum for measurable protection, but 30 gives meaningfully more defense against sunburn. Higher numbers add some extra protection, but no sunscreen blocks 100% of UV rays.

Third, check for water resistance if you plan to swim, sweat heavily, or spend time near water. AAD notes that water resistance lasts either 40 or 80 minutes — the label will say which. “Water resistant” does not mean waterproof; it means the protection holds up for a limited time while you’re wet, and you reapply after that window.

SPF Numbers Don’t Measure Time

One of the most common misconceptions is treating SPF as a time clock. The FDA is explicit: SPF measures the level of sunburn protection from UVB, not how long you can stay in the sun. An SPF 50 product does not let you stay out five times longer than SPF 10.

This misunderstanding is why many people skip reapplication or stay out too long. Sunscreen effectiveness depends on consistent, correct use, not just the number on the bottle. The same logic applies to the “waterproof” misconception — that word no longer appears on legitimate labels because no sunscreen is truly waterproof.

How to Apply Sunscreen Correctly

Even the best bottle fails if applied wrong. The FDA recommends applying sunscreen regularly and as directed, with reapplication at least every 2 hours. That two-hour clock restarts after swimming, heavy sweating, or towel drying.

Most people under-apply by a wide margin. A common guideline is about one ounce — a full shot glass — to cover exposed skin, ensuring the labeled SPF actually applies. Don’t forget easy-to-miss spots like the ears, back of the neck, tops of feet, and the part line in your hair. On cloudy days, UV rays still reach the ground, so the FDA recommends using sunscreen even when the sun isn’t visible. Sunscreen also works alongside shade, clothing, hats, and sunglasses — no single method does the whole job alone.

If you’re exploring options with texture or glow benefits, our tested roundup of the best asian sunscreen for dry skin breaks down formulas that feel lighter while still offering solid protection.

Common Sunscreen Mistakes to Avoid

• Buying on SPF alone. Skipping the broad-spectrum check means you might be protected from UVB but not UVA. High SPF without broad spectrum is a half-measure.
• Assuming higher SPF means total protection. SPF 100 blocks more UVB than SPF 30, but no product blocks all rays. The FDA states that no sunscreen blocks all UV radiation.
• Treating water resistance as a pass to skip reapplication. The 40- or 80-minute limit on the label applies to active water time, not all day.
• Skipping sunscreen on cloudy days. UV rays penetrate cloud cover, which is why AAD guidance emphasizes daily use regardless of weather.

FAQs

Does Higher SPF Mean I Can Stay Out Longer?

No. SPF measures the amount of UVB protection, not time in the sun. The FDA explicitly states SPF is not a time measurement. You still need to reapply at least every 2 hours regardless of the SPF number on your bottle.

Is Spray Sunscreen as Effective as Lotion?

Spray sunscreens work when applied generously and rubbed in, but they’re easy to under-apply because coverage is hard to see. The FDA recommends applying regularly and as directed. If you prefer spray, apply until the skin glistens, then rub it in, and consider a lotion for the face.

Can I Use Last Year’s Sunscreen?

Only if it hasn’t passed its expiration date and shows no changes in color or texture. The FDA requires sunscreens to maintain their strength for at least three years, but heat and time can degrade them. When in doubt, replace it and try our top-rated picks for dry skin.