Take A Number: How To Choose The Right SPF For You

by Gio
how to choose the right spf number for your needs and lifestyle

“30 or 50? 15 is definitely too low but where’s the catch if I go too high?”

I’m talking about SPF numbers. How the heck do you choose the one that’s right for you? Like, can you get away with a lower SPF if you don’t go to the beach or is it better to aim high in winter, too?

Here’s a quick guide to help you figure out the protection SPF numbers give you and how to choose the best one for your needs and lifestyle:

How Does SPF Work?

Nope, SPF doesn’t tell you how well a sunscreen protects you from UV rays. It tells you only how well it protects you from UVB rays.

In other words, SPF simply determines the amount of time you can stay in the sun without burning. Here’s an example. Let’s say your skin starts to burn after 20 minutes of unprotected sun exposure. If you use SPF 15, your skin will take 15 times longer to burn.

But even this is misleading. You see, when scientists determine SPF, they use a lamp that emits a constant stream of light. In real life, UVB rays are stronger in the afternoon and weaker in the early morning and early evening. So, even if you wear SPF 15 all day, it’ll take you way longer to burn in the early morning than in the early afternoon!

And that’s not even the whole story! UV filters get used up as they do their job. The more sunlight they’re exposed to, the sooner they degrade. You know what that means? There’s no way that SPF 15 is gonna last you 5 hours. At the beach, it becomes useless after 2!

WARNING: I’m gonna tell how to choose the right SPF number for you now. But make sure your sunscreen protects your from UVA rays as well. If you don’t know if your sunscreen provides adequate UVA protection, check out this post to find out.

Related: Do You Really Need To Reapply Sunscreen Every 2 Hours?

How effective is your sunscreen? Sign up to the newsletter below to receive the β€œSunscreen Audit” Worksheet and find out if your sunscreen is really up to the job:

SPF Under 15: Don’t Bother

It’s rare to find a sunscreen with SPF lower than 15. For a good reason: they don’t provide adequate sun protection. If you come across SPF 11 or something, it’s usually on foundations or tinted moisturisers. By all means, use them to even out your skin tone or moisturise your skin, but don’t expect any real sun protection from them. Cosmetics with SPF are NOT a substitute for sunscreen.

Related: Do Cosmetics With SPF Provide Adequate Sun Protection?

bioderma cicabio spf 50

SPF 15: Barely Enough For Winter Days

SPF 15 is the minimum recommended by derms for daily, casual wear.

FYI, casual wear doesn’t mean you can put your sunscreen on today or forget all about it tomorrow. Casual wear means “days when you’re not getting much sun exposure.”

You know what I’m talking about. It’s the middle of winter. The sun hides behind dark gloomy clouds. Maybe it makes a brief appearance, too.

Either way, you’ll barely see it. You get out of the car just to walk to your office or run brief errands. Who wants to be outside in this freezing cold?

On days like this, a SPF 15 is just about enough. It blocks a whopping 93% of UVB radiation. Sounds like a lot, doesn’t it? Until you realise that 7% of UV rays still make it past it and hurt your skin.

In winter, this ain’t a big problem, but in summer? You definitely need to up your sun protection then.

Related: Do You Need To Wear Sunscreen While Driving?

SPF 30-50: Best For Spring & Summer Protection

You may think there’s a huge difference between SPF 30 and SPF 50. Until you look at the real numbers:

SPF 30 blocks nearly 97% of UVB rays while SPF 50 98%. Who would have thought the difference was so minimal?

If the sun’s shining and you’re spending any time outdoors – even if it’s just taking your dog for a walk – or are sitting for hours near a big window, you need an SPF in this range.

SPF 30 is the one I choose for everyday wear even in winter (I’m just not comfortable with SPF 15). In summer, I up to SPF 50. Better safe than sorry, right?

Related: Do You Need To Wear Sunscreen Indoors Too?

SPF 50+: Better Summer Protection (But The Texture’s Worse)

The verdict’s out: the higher the SPF, the better sun protection you’re getting. SPF 50+ can block up to 99% of UV rays. As long as you’re careful with reapplication.

Here’s the deal: the higher the SPF is, the thicker and unpleasant the texture becomes. Makes sense. If you want to increase the SPF, you need to use a bigger dose of UV filters. And those are often oily/greasy.

So you apply a bit less. I mean, it’s SPF 100. I don’t need a generous dose, right?

Wrong! If you apply less than the recommended amount (1/4 of a teaspoon for the face and a small glass shot for the body), you’re reducing the SPF and compromising your protection.

You may also think you can get away with reapplying a high SPF less often. Again, wrong! Its UV filters still get used up.

Bottom line: with higher SPF numbers, there’s a trade off. They provide better protection if you’re religious with application. Skimp on that and all you’re left with is a false sense of security that leads to sun damage.

If you can tolerate the unpleasant texture and are willing to use it properly, SPF50+ is a great choice. If not, SPF 30/50 will do job just fine.

Related: Does SPF 100 Provides Better Sun Protection Or Just A False Sense Of Security?

The Bottom Line

Always go with the highest SPF your skin can tolerate and reapply it generously. Whatever you do, never go below SPF15. Low SPFs let the sun do too much damage.

What SPF number are you using? Share your picks in the comments below.



Ruth July 21, 2015 - 4:28 pm

Great post as always.

Gio July 21, 2015 - 5:30 pm

Ruth, thanks! Glad you liked it. πŸ™‚

bebe July 21, 2015 - 4:36 pm

I’m currently using Clarins UV Ecran SPF 40. I like the texture of the product very much.
I use a sun screen around spf 50 regardless of the weather, season or what I’m doing. I’m just not bothered with juggling sun screens and I have a very pigmentation-porn skin.

Gio July 21, 2015 - 8:20 pm

Bebe, glad you’ve found a sunscreen you love. I agree, no point changing it if that works so well for you. πŸ™‚

MonicaP July 21, 2015 - 5:14 pm

I stick to the 30 – 50 range. I find that these work, but I can still get a bit of color πŸ™‚


Gio July 21, 2015 - 5:33 pm

Monica, I still get a bit of colour too. Sadly, no sunscreen protects from all UV rays. 2 or 3% of them still pass through, darkening skin a bit. But those in the 30-50 range provide the best protection imo. Not too low to be work well, but not too high to provide a false sense of security.

Allison July 21, 2015 - 11:11 pm

I have a slew of sunscreens most from SPF 28-50. And now I am wearing a hat with UPF 50. On the beach, I sit under an umbrella with UPF 50. But as you said, the rays do get through. Sadly, I can’t undo the damage done years ago, but I am quite serious about it now. Beautyholics Anonymous was writing about a lightweight sunscreen (spf 30 or 50) she brought back from Japan called a “water gel”. I wish we had those here. I usually use physical sunscreens with titanium dioxide and zinc oxide but they can be so heavy. And on occasion, I’ll use a spray sunscreen but I’m never sure that it really covers enough to work well.

Gio July 22, 2015 - 9:42 am

Allison, I feel the same. If I think back on all the days I spent in the sun without sunscreen… *cringes* But it’s great that we know better now. And you’re so diligent, I’m sure you won’t suffer any further damage from the sun.

I avoid spray sunscreens because it is very difficult to see if you’ve applied them properly. They usually go on clear, so it’s easy to miss a spot. But I hope those water gel sunscreens will reach the rest of the world soon. They sound fab! πŸ™‚

Janessa July 23, 2015 - 12:00 am

You can get some Japanese sunscreens on Amazon! Like Biore Watery Essence sunscreen! It’s really lightweight. I would test it first out on a not so blazing day and see how that works for you! I love it for milder sun exposure days. I’ve repurchased that product multiple times and while I love it, I ultimately prefer Shiseido Perfect UV Protector SPF 50 (It’s a white pearly bottle with a blue line across for reference which I got from Asia, but still wanted to recommend my all-time current favorite) because I can decipher the ingredients and know I’m well-protected. The product comes with multi-language pamphlet is why hehe.

Some websites like sasa . com ship to the US and sell Asian beauty products. It’s a well-trusted retailer in Asia. :] Good luck!

Gio July 23, 2015 - 9:40 am

Janessa, thank you for the tips!!

H January 10, 2016 - 7:35 pm

Janessa, I would be wary of them on Amazon. (1) You don’t know how they are being stored. (2)You don’t even know if you are getting a legit product.(3) They may be expired and you might not know it. Even if it does have an expiration date, and it says it isn’t expired, it could have expired sooner because it was not stored properly. The info about when it expires often isn’t indicated on the packaging.

Janessa July 22, 2015 - 11:51 pm

I use an SPF 50 or SPF 30. With SPF 50, I’m more forgiving about being a physical and chemical blend, primarily favoring physical. With and SPF 30, I better get around 18% zinc oxide with or without titanium though that’s not always so. Even with an SPF 50 claim of let’s say 10% TiO2 and only 5% ZnO, I’m going to treat that SPF 50 product for light-sun-exposure use because of the insufficient UVA blockage.
I prefer chemical sunscreens for running or being active outdoors for an hour or two because it doesn’t have a white cast and most are really water resistant and most importantly, affordable. I’ve found most (non-fancy) physical sunscreens sweat off in white (probably then with a mild grey cast due to dirt) and it’s not aesthetically appealing.
If I’m outdoors for a good chunk of the day, I opt for a physical sunscreen so I can reapply and not worry about it sinking in first. I wouldn’t mind white casts at that point, since it’s not often I’m out all day and if I were on an outdoor adventure, I could less.
While I’ve tried several really nice, sweat-proof, long-lasting physical sunblocks, they’re far too costly for frequent exercise use out of doors.
I’ve recently seen Tinsorb in the states! It’s an import product from Korea so I don’t think it’s quite common in American brands. I haven’t tried any sunscreen with that yet, but I’m curious.
I also opt for mostly physical ingredients when I can because chemical sunscreens seem toxic (I realize it’s not proven(?) but if I can pick, why not?), especially for my intended use: wearing while exercising.

Janessa July 22, 2015 - 11:53 pm

I want to add that I’m not longer worried about light, unprotected sun exposure as I do believe the sun is good. I always have sunscreen on my face though so I’m mostly referring to arms and legs. ;]

Gio July 23, 2015 - 9:49 am

Janessa, both chemical and physical sunscreens have their pros and cons, don’t they? But it’s great to have the option to choose between them based on our needs and what we are going to do that day.

I like Tinosorb. It is very used in Europe and it works well for me, but as you know, I prefer zinc oxide-based sunscreens. I like that they work immediately and last a bit longer. I wouldn’t say chemical sunscreens are toxic. They can cause allergies and some of them get absorbed by the body, which may be bad (there are no studies on this yet) for women who are pregnant or breastfeeding, but they won’t kill you.

The sun may be good for us, but in moderation. A tan is the body’s natural self-defense mechanism against UV rays. So, if your skin starts to tan, that’s your body’s way of telling you “get out of the sun!”. So, if you’re not using sunscreen, be careful not to get a tan.

Janessa July 23, 2015 - 5:37 pm

Thanks for the response, Gio! Living in such a sunny climate where most forgo it’s tempting to, as well. I’ve tanned slightly and should take more precaution in caring for my skin. :]

Janessa July 23, 2015 - 5:37 pm

forgo sunscreen*

Gio July 23, 2015 - 6:19 pm

No worries. I tend to be too paranoid about sunscreen maybe, so it’s good to be reminded that a bit of sun isn’t that bad for you. But we can’t even be too careless. Everything in moderation. πŸ™‚

K July 23, 2015 - 10:46 pm

Do you have any tips on how to remember to reapply sunscreen? I always forget to apply some before I leave work.

Gio July 24, 2015 - 10:23 am

K, I usually either stick post-it notes on my desk or create a memo note on my phone. πŸ™‚

audrey March 8, 2017 - 4:00 am

i try this approach when i see the sunlight, i always ask to myself, “when was the last time i apply/reapply my sunscreen” so it became a habit and more like a reflex after i practice it a few years

Gio March 9, 2017 - 6:26 pm

Audrey, well done!

audrey March 8, 2017 - 3:57 am

I have been using spf 30 for the past few years and didn’t even realise that the titanium dioxide in my tinted moisturizer is what transformed my skin for the better. i thought that it was a magical tinted moisturiser and i keep on repurchasing it! i went from dull dry dehydrated skin to the point where strangers asked me what i use for my skin and they even demand to know the name of my dermatologist. Sunscreen is such a vital part of my life now. Wish i started earlier, i started when i was 21 πŸ™‚ been thinking to upgrade my sunscreen to spf 50 (22% zinc oxide), i heard Bareminerals Prep Step Mineral Shield SPF 50 is great, have you tried it before?

Also, what do you recommend for drugstore cleansing oil that’s suitable for sensitive eczema-prone skin? I have rosacea on my face and eczema (atopic dermatitis) for the rest of my body and io have been avoiding soap (SLS products) like crazy these past few months because my skin got to the point where it’s just angry at me and giving me bad eczema flare-ups.

Gio March 9, 2017 - 6:32 pm

Audrey, that’s wonderful. You started fairly young, trust me. I know women much older who still don’t use it daily!

The Bare Minerals is a great choice. πŸ™‚ As for cleansing oils, have you tried hemp seed? That’s very gentle and moisturizing. Evening primrose is another good choice because it has soothing properties. You could even mix the two. πŸ™‚

audrey March 10, 2017 - 4:37 am

I started using it when I was little but only during beach vacations or Scout outdoor programs at school, so not everyday. But when I was 21 I finally promise myself to use it everyday, even if I don’t do anything fancy for my skin (anti-aging creams, eye creams, fancy serums & moisturisers, procedures) like everyone else around me. Turns out it doesn’t have tpo be all fancy and expensive to treat our skin right.

I love that you also choose physical sunscreen over chemical sunscreen πŸ™‚ It’s gentle for sensitive skin, never stings like chemical sunscreen & apparently a good reflector of UVA and UVB at the same time. I’m glad you think Bareminerals Prep Step Mineral Shield SPF 50 is a good choice because I have been wanting to try it for the longest time but a bit hesitant since it’s $30/30ml (around $50ish with international shipping and everything), now I’m convinced and will try it after my Bareminerals Complexion Rescue Tinted Hydrating Gel Cream SPF 30 with Titanium Dioxide 6.5% finished. I love it and have been repurchasing it over and over again these past 2 years but the 22% zinc oxide sounds so much better than 6.5% titanium dioxide, especially for UVA protection.

I haven’t tried cleansing oil at all, I saw Avene’s XeraCalm Cleansing Oil (XeraCalm is their Atopic Dermatitis and Eczema special bodycare line) but it doesn’t contain any carrier oil, it just has mineral oil in it. Do you think it’s better for me to buy Hemp Seed and Evening Primrose Oil then mix it myself instead of Avene’s XeraCalm Cleansing Oil?

Gio March 17, 2017 - 7:28 pm

Audrey, 90% of premature aging is caused by the sun so if you don’t use sunscreen every day, all those fancy creams are useless. You’re gonna age a lot better than your friends just for doing that. πŸ™‚

As for the oil, it depends. Both options are good. It just depends on which one suits your skin and your lifestyle better.

audrey March 18, 2017 - 2:58 pm

I agree. I have been faithful in applying sunscreen but mostly a bit slacking on reapplication (a lot of times i forgot to reapply every 2 hours). I put it in my makeup pouch now so I’m always reminded to reapply everytime I open my makeup pouch to reapply lip balm/lipstick.

Gio March 18, 2017 - 4:16 pm

Smart girl! I should do the same. πŸ™‚

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