Sunscreen: how much to use, which SPF and how often to reapply
How much sunscreen to use on your face, SPF 30 vs 50, what broad spectrum means, how often to reapply and how to wear sunscreen under makeup.
By the Green Point editorial teamUpdated 6 min readKey takeaways
- Use a broad-spectrum sunscreen with SPF 30 or higher every day on skin that clothing doesn't cover.
- For your face, dermatologists suggest at least 1 teaspoon, roughly two finger-lengths of product.
- Reapply about every 2 hours outdoors, and straight after swimming, sweating or toweling off.
- SPF 30 blocks about 97% of UVB rays and SPF 50 about 98%; how much you apply matters more than the jump.
- Makeup with SPF is a bonus, not a replacement: wear a real sunscreen underneath.
On this page
- What SPF and broad spectrum mean
- SPF 30 vs SPF 50: which should you use?
- How much sunscreen should you put on your face?
- How often should you reapply sunscreen?
- Do you need sunscreen every day, even when it's cloudy?
- Sunscreen under makeup: does makeup with SPF count?
- Mineral or chemical filters?
- Frequently asked questions
Use a broad-spectrum sunscreen with SPF 30 or higher every day on exposed skin. For your face, the American Academy of Dermatology suggests at least 1 teaspoon, about enough to cover the length of your index and middle fingers. Apply it about 15 minutes before going out and reapply every 2 hours outdoors, or right after swimming or sweating.
What SPF and broad spectrum mean
Sunlight contains two kinds of ultraviolet (UV) rays that harm skin. UVB rays cause sunburn. UVA rays reach deeper, drive wrinkles and dark spots, and also contribute to skin cancer. A good sunscreen needs to cover both.
- SPF (sun protection factor) measures protection against sunburn, which is mostly UVB.
- Broad spectrum on a US label means the product passed a test for UVA protection as well as UVB.
- UVA in a circle on European packs means the UVA protection meets the EU standard relative to the SPF.
- UVA stars (used in the UK) rate UVA protection from 1 to 5; the NHS suggests at least 4 stars.
If a sunscreen shows only an SPF number and no UVA claim, assume it mainly protects against burning. Pick one that clearly states UVA or broad-spectrum protection.
SPF 30 vs SPF 50: which should you use?
In lab tests, SPF 30 filters about 97% of UVB rays and SPF 50 about 98%. No sunscreen blocks 100%. Dermatologists recommend at least SPF 30 for daily use, and many suggest SPF 50 for long days outdoors, at high altitude or near water and snow.
The bigger difference in real life is the amount. SPF is measured with a thick, even layer, and most people apply much less than that. A generous layer of SPF 30 can protect better than a thin smear of SPF 50. A high number also doesn't let you stay out longer without reapplying.
| Situation | Suggested sunscreen |
|---|---|
| Everyday errands, commute, office with windows | Broad spectrum, SPF 30 or higher |
| Hours outside, beach, hiking, skiing | Water-resistant, broad spectrum, SPF 50 |
| Swimming or heavy sweating | Water-resistant, reapplied after every swim or towel-off |
| Dark spots or melasma | Broad spectrum SPF 30+, ideally tinted (iron oxides help with visible light) |
How much sunscreen should you put on your face?
The AAD advises at least 1 teaspoon for your face, about the length of your index and middle fingers. For your whole body in a swimsuit, most adults need about 1 ounce, the amount that fills a shot glass. Don't forget your ears, neck, the back of your hands and your lips (use a lip balm with SPF 30+).
How often should you reapply sunscreen?
Reapply about every 2 hours when you're outdoors, and straight away after swimming, sweating heavily or drying off with a towel. Sunscreen rubs off, breaks down in sunlight and wears away with sweat, even if the label says water resistant.
Water resistant means the product keeps working for a tested time while you swim or sweat. In the US the label must say either 40 or 80 minutes. No sunscreen is truly waterproof or sweatproof, and US rules don't allow those words on the label.
Do you need sunscreen every day, even when it's cloudy?
Yes, if you'll be outside at all. Up to 80% of UV rays can pass through clouds, and UVA is present all year, including in winter. Daily use is one of the most effective things you can do against sunburn, skin cancer, wrinkles and crow's feet and dark spots.
Sunscreen works best as part of a bigger plan. Seek shade around midday, wear a wide-brimmed hat and sunglasses, and cover up with clothing. Keep babies under 6 months out of direct sun and ask a doctor before using sunscreen on them.
Sunscreen under makeup: does makeup with SPF count?
Foundation, powder or tinted moisturizer with SPF helps a little, but you would need to apply far more than anyone does to reach the SPF on the label. Treat it as a bonus layer, not your sunscreen.
- Apply your usual skincare, then sunscreen as the last skincare step in the morning (see our skincare routine order guide).
- Wait a few minutes until it has set and no longer feels wet.
- Apply makeup on top, pressing rather than rubbing so you don't move the sunscreen around.
- To top up during the day, use a sunscreen stick, mist or SPF powder over makeup. These are easier than starting over, though harder to apply generously.
Mineral or chemical filters?
Sunscreens use mineral filters (zinc oxide, titanium dioxide), organic or "chemical" filters, or a mix. Dermatologists often recommend mineral formulas for sensitive skin. Some chemical filters have raised questions about hormone effects, and rules differ between the EU and the US. We compare them in detail in mineral vs chemical sunscreen. Whatever you choose, the best sunscreen is the one you'll wear every day.
Green Point rates UV filters cautiously: regulated filters and suspected endocrine disruptors lower a product's score. That's a precautionary view of the ingredients, not advice to skip sun protection. If a sunscreen you like scores lower, compare a few options and keep wearing sunscreen while you decide.
Frequently asked questions
Does sunscreen expire?
Yes. In the US, sunscreens must keep their original strength for at least three years, and many show an expiry date. Throw out sunscreen that is past its date, has changed in color or texture, or has been stored in a hot car or beach bag for a long time. If you use the right amount every day, a bottle won't last long anyway.
Do I need sunscreen indoors?
If you spend most of the day away from windows, you probably don't need it. UVA rays pass through ordinary window glass, though, so if you sit near a window, work in a sunny room or drive a lot, daily sunscreen on your face and hands makes sense. Applying it every morning as part of your routine is the simplest way to never think about it.
How long before going outside should I apply sunscreen?
Apply it about 15 minutes before you go out, so it has time to settle into an even film on your skin. This matters most if you're heading straight into water or are likely to sweat. In the morning, putting sunscreen on as the last step of your routine, before makeup, usually gives it plenty of time.
Is a higher SPF worth it if I have darker skin?
Everyone can get sunburn, sun damage and skin cancer, whatever their skin tone, so the same advice applies: broad spectrum, SPF 30 or higher. If you have dark spots or melasma, a tinted sunscreen with iron oxides can help, because visible light can also darken pigmentation. Tinted formulas can also avoid the white cast some mineral sunscreens leave.
Sources
- How to apply sunscreenAmerican Academy of Dermatology
- Sunscreen FAQsAmerican Academy of Dermatology
- Sunscreen: How to Help Protect Your Skin from the SunU.S. Food and Drug Administration
- The Skin Cancer Foundation Offers Tips on Choosing and Using SunscreenThe Skin Cancer Foundation
This guide is for general information and is not medical advice. If you have a skin, allergy or health concern, talk to a doctor, dermatologist or dietitian. Green Point scores and Skin Scan results are informational and are not a diagnosis.
