How Often Should You Reapply Sunscreen? 

You meticulously applied a solid coat of SPF 50 to your face and body this morning and are now ready to take on the day, sunburn-worry free. Right? Not necessarily. This guide breaks down some helpful advice on how often you should reapply sunscreen. Hint: it varies! 

How Often to Reapply Sunscreen 

As a general rule, your sunscreen will start to lose its effectiveness after a 80 minute period. So, if you’re spending the day outside, regardless of whether you’re running a marathon or just napping by the pool, you’re going to want to reapply on a consistent two-hour cadence. On top of this, frequent in-and-out-of-water activity requires more reapplication, even if your sunscreen is labeled as water resistant.   

Why Is Reapplying Sunscreen Important? 

Many sunburns occur when a user has a false sense of security. Maybe you sprayed yourself once with SPF 30 in the morning, but then went about your day as if you were encased in a magic shield. You’re not. Several factors make reapplying sunscreen critical to keeping your skin protected:  

• Most people don’t apply sunscreen correctly in general. Re-application at least increases the chances of more thorough coverage.  
• The intensity of the sun’s rays varies throughout the day. So, if you put on sunscreen in the morning, it’s important to re-up during peak hours (typically between 10 a.m. and 2 p.m.) That’s when the sun will find any crack in your suit of armor.  
• Finally, being outside usually involves activity, which means sunscreen tends to wear off with excessive movement. Whether it’s through sweat, toweling off or making sand angels, you’ll need to reapply your sport sunscreen on your big day out.   

How Much Sunscreen Do You Need? 

Don’t overestimate the power of your sunscreen. Chances are, you didn’t apply enough of it. For the average-size human, a shot glass of sunscreen (1.5 ounces) applied to the face and body before each outing should be enough coverage for a two-hour period. In addition, it’s a good idea to add an extra layer to the more sensitive exposed areas, like your nose, lips, neck and ears.

Read more: Does Sunscreen Expire?

How Long After Reapplying Sunscreen Should You Wait to Go Outside? 

Sunscreen takes time to fully dry. After reapplying, give yourself at least 10 to 15 minutes before venturing back out into the open sky.  

How Often Should You Reapply Sunscreen While Indoors? 

Believe it or not, you’re still subject to the damaging effects of the sun even when you’re indoors. While sunburn-inducing UVB rays don’t penetrate windows, certain UVA rays do, resulting in skin damage and accelerated ageing over time. Because of this, the answer is yes: you should reapply broad spectrum sunscreen while indoors, especially if you’re exposed to sunlight through a window without UV-protective film.  

FAQs About How Often to Reapply Sunscreen 

Do You Really Need to Reapply Sunscreen Every 80 minutes?

Yes, one application of sunscreen isn’t going to last you all day. In fact, the false belief you’re fully covered without reapplying is when the most punishing sunburns occur.  

How Long Does SPF 50 Last?

Regardless of SPF level, sunscreens lose their protective superpowers over time. Make sure you’re reapplying SPF 50 every 80 minutes — more frequently if you’re going in and out of the water.  

How Bad Is It to Not Reapply Sunscreen?

If you’re not reapplying sunscreen intermittently, you’re decreasing the chances of having proper sun protection throughout the day. The clock starts at around 80 minutes after your first application.