The Most Important SPF Number You Need to Know

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A shelf full of different SPF sunscreens can present a touch choice—especially when the goal is a low-key day of lounging poolside. Even taking into account different skin tones, genetics and environmental variables one thing is universally certain: using SPF 30 or above is ideal. To learn more, we’ve checked-in with dermatologists Joshua Zeichner, MD, and David A. Colbert, M.D., who both agreed that the higher the better is the motto for all.

What is the main difference between SPFs?

The main difference between each SPF is the amount of UVB ray (the rays that provoke sunburn) protection it provides. "An SPF 15 product blocks about 94% of UVB rays, SPF 30 product blocks 97% of UVB rays, and an SPF 45 product blocks about 98% of rays," Colbert says, adding that sunscreens with higher SPF ratings block slightly more UVB rays, but none offers 100% protection.

How often should I apply SPF?

It's important to wear SPF everyday (wearing SPF-infused makeup is a great solution), even when not directly in the sun for a long period of time. When it comes to SPF application, Zeichner suggests starting with a higher SPF and re-applying every 2 hours for maximum coverage (a routine he claims many people fail to abide by). "If you aren't applying it as much, then you're not getting the protection stated on the bottle," he says. "It's a method of proper use and reapplication."

Broad Spectrum Sunscreens

When choosing an SPF for your face and body, Zeichner says to make sure the label of the sunscreen always states broad spectrum. "This way you know you're getting UVA ray protection as well, which is more responsible for causing aging and skin cancers." Below, we've rounded up some of our favorite broad spectrum, high-SPF formulas.

SPF 50

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For a matte finish that protects all skin types, try SkinCeuticals Physical Matte UV Defense SPF 50 ($34; When using a stick sunscreen, Zeichner recommends swiping against the cheeks four times for better protection. We love Neutrogena Beach Defense Water + Sun Protection Sunscreen Stick Broad Spectrum SPF 50 ($11;, which is an effective water-resistant solution. If you have a darker complexion, opt for a tinted sunscreen like the La Roche-Posay Anthelios 50 Body Mineral Tinted Sunscreen ($29;, which leaves a natural finish and is safe for sensitive skin.

SPF 30

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When it comes to lighter skin, Colbert suggests using an SPF 30 or above. We love tarte's Tarteguard 30 Sunscreen Lotion Broad Spectrum SPF 30 ($12; and Clinique's Sun SPF 30 Face Cream ($22; These antioxidant-rich formulas work to combat aging, while also protecting and leaving the skin looking youthful in the process. For a sheer, lightweight blend that's perfect for the face, opt for L'Oreal Paris' Advanced Suncare Silky Sheer Lotion SPF 30 ($8;

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