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

How do you choose the right SPF number? Summer is here and sun protection from the glorious sun rays a top priority for many of us. But what’s the best number? As I was growing up, everyone swore 15 was enough. Now you have SPF 100 and beyond. Even 50 sounds too little sometimes… And what about winter? Can you choose a lower number then or is it ok to use the same SPF all year round?

So many questions! Luckily, I’ve got answers. 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?

First things first. SPF stands for Sun Protection Factor. If you grew up in the 80s or 90s, you’ve probably been told that SPF tells you how well a sunscreen protects you from UV rays. Unfortunately, that’s not true. SPF tells you only how well a sunscreen protects you from UVB rays.

What does that mean exactly? 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 you 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?

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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. I’m always surprised when I come across a tinted moisturiser or foundation tight boosts SPF 11 or something. It’s so little, why even bother putting it on the packaging? You’re just tricking people into a false sense of security! Now, I’m not saying these products are bad. A foundation may have an SPF of 8 and provide no adequate sun protection, but still give your skin a glowy, flawless base. By all means, if you find a product you like with a low SPF, use it – just NOT as sunscreen.

While we’re on the subject, cosmetics with SPF are NOT a substitute for sunscreen. You need something crazy like 7 layers of foundation to reach the SPF stated on the bottle – and that’s assuming the SPF is high enough to do something!


  • Estee Lauder Double Wear Stay-In-Place Foundation SPF 10 (Β£37.50): Let’s be honest. This foundation won’t provide any helpful sun protection. But its medium-to-full coverage effortlessly hides every imperfection, drying to a matte finish. It’s available in 60 shades, so everyone will be able to find a good match. Available at Boots, Estee Lauder, Harrods, Selfridges, and Sephora.

Related: Do Cosmetics With SPF Provide Adequate Sun Protection?

bioderma cicabio spf 50

SPF 15: Barely Enough For Winter Days

When I was growing up, most skincare products boosted a SPF of 15. I thought that was the norm and high enough to provide adequate sun protection against UV rays. πŸ˜“ How naive I was! SPF 15 is enough for the gloomiest of winter days… barely.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 could work – especially if you live in a place where you barely get any sun in winter all. But in summer? SPF 15 isn’t gonna cut it then.


  • Nivea Sun Protect & Moisture Sun Cream Lotion SPF15 (Β£6.00): A moisturising chemical filter for dry skin that provides just about enough protection for winter. It’s too rich for oily skin, though. Available at Boots and Sephora.
  • Sun Bum Sunscreen Lotion SPF 15 ($18.49): A moisturising sunscreen that provides broad spectrum (but low!) protection from both UVA and UVB rays. It has a smooth texture that dries quickly onto your skin. Available at Ulta.

Related: Do You Need To Wear Sunscreen While Driving?

SPF 30-50: Best For Spring & Summer Protection

Why did I put SPF 30 and SPF 50 in the same category? Surely, there’s a massive difference between them… Not so much. Let’s take a 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?

SPF 30 to 50 is what your skin needs when the sun is around. Whether you’re walking the dog, sitting for hours near a big window in your office, or jogging outside in the early morning, this is the time to take out your SPF 30 or even 50. For me, it really depends on the weather and what I’m doing.

In winter, I go for SPF 30. It doesn’t matter if I can’t see the sun or I venture out just for grocery shopping, I’ll always slather on SPF 30 before leaving the house. In summer, when the sun rays are stronger, I up my sunscreen game to SPF 50. I’m so pale that, if I wear anything lighter, I’m bound to burn.


  • EltaMD Lotion Broad-Spectrum SPF 30 Plus ($43.00): A moisturising sunscreen with zinc oxide that protects you from head to toe. It’s best suitable for dry skin. Available at Dermstore.
  • La Roche Posay Anthelios Mineral Ultra-Light Face Sunscreen Fluid SPF 50 ($37.99): A lightweight mineral sunscreen that provides high-broad spectrum protection without leaving a white cast or greasy residue behind. Available at Boots and Ulta.
  • Supergoop! Mineral Mattescreen SPF 40 ($38.00): Perfect for oily skin, this mineral sunscreen provides broad spectrum and minimises the look of pores, for a flawless, matte finish. Available at Blue Mercury, Cult Beauty, Revolve, SpaceNK, and Ulta.

Related: Do You Need To Wear Sunscreen Indoors Too?

SPF 50+: Excellent Sun Protection (But The Texture’s Worse)

The verdict’s out: the higher the SPF, the better sun protection you’re getting.Β SPF 50+ can block up to 99% of UV rays. As long as you’re careful with reapplication. But, there’s a catch: the higher the SPF is, the thicker and more unpleasant the texture becomes. Makes sense. If you want to increase the SPF, you need to use a bigger dose of UV filters. And UV filters 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, making the sunscreen useless after several hours. As a rule, the longer you stay in the sun, the faster your sunscreen gets all used up and the more often you need to reapply it.

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.


  • La Roche Posay Anthelios Clear Skin Dry Touch Face Sunscreen SPF 60 ($19.99): This lightweight chemical sunscreen soaks up excess oil while providing high, broad-spectrum sun protection that keeps your skin safe even in the hotter summer days. Plus, it dries to a matte finish. Available at Boots, Dermstore, and Ulta.
  • Neutrogena Ultra Sheer Dry-Touch Sunscreen Lotion Broad Spectrum SPF 70 ($15.99): A chemical sunscreen with sun proaction and oil-absorbing properties that protects your skin without leaving a greasy residue behind. Available at Ulta.
  • Sun Bum Face Lotion SPF 70 ($15.49): A high, broad-spectrum sunscreen with such a lightweight texture, it doesn’t leave a greasy residue behind. Ideal for oily skin, but anyone can use it. Available at Ulta.

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

The Bottom Line

The best sunscreen is the one you can use. You may think that SPF 100 provides the best protection, but if it’s so greasy you hate using it, you won’t apply enough and it won’t protect you from wrinkles and sunburns. 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 to your precious skin.