You’ve probably heard that you need 1/4 teaspoon of sunscreen to cover your face. This quantity is calculated from an estimate of people’s face sizes, and the amount of sunscreen they use in SPF testing (2 mg per cm^{2}). Since it’s based on the thickness of sunscreen, a larger face will need more sunscreen, while a smaller face will need less sunscreen. But how much sunscreen would *I* need?

Because I have an unusually large forehead and a flat-but-wide nose, I didn’t want to use a rough geometric estimate, and opted for a more empirical (and hopefully accurate), fiddlier measurement method instead. I decided to work out my facial surface area by covering my face with paper tape, then taping it onto grid paper and counting the area. Of course, I filmed the process! I then worked out how much sunscreen I needed for my face, and I also worked out how much sunscreen I needed for my neck and decolletage.

The materials I used:

**Paper tape**: I used a generic version of 3M Micropore**Grid paper**: I used a grid spacing of 0.5 cm and heavier lines of “2”

Here are the other estimates that people have come up with (different people have different faces, so these may not be relevant to your situation – when in doubt go with the full 1/4 tsp):

- SCCS (EU): 25th percentile of women’s faces (half head) = 565 cm
^{2}(I made a mistake here in the video, sorry – it was a Dutch study, not a Danish study!) - John (Futurederm): Rectangular estimate = 620 cm
^{2} - Korean TV show (I can’t find the link anymore unfortunately, let me know if you have it!): Grid sticker overlaid on male face = 400 cm
^{2} - Reddit (/u/avecsagesse): Divided face into rectangular zones = 364.5 cm
^{2} - Reddit (/u/littlepinkkitty): Estimated face as an oval = 362 cm
^{2}

*Related post: How SPF Changes With How Much Sunscreen You Use*

Here’s what my grid looked like after I stuck all the tape down, with all my working for counting the squares:

Here are my measurements, and the conversions to 1/4 teaspoon amounts:

**Edit**: Out of curiosity, I also tried estimating my face as an ellipse and as a circle to compare with the numbers I got from the tape method:

- Face height: 20.5 cm
- Face width: 26 cm
- Estimate as an ellipse (A = πab): 418.62 cm
^{2}(9.9% difference) - Estimate as a circle (estimate radius as the average of the two axes, A = πr
^{2}): 424.56 cm^{2}(11.4% difference)

The accuracy of this method depends on how protruding your features are, but it isn’t a bad estimate if you don’t want to spend 40 minutes applying tape to your face.

Official sunscreen usage recommendations:

*Related post: Video: All Your Sunscreen and Makeup Questions Answered*

# Other references

Density of mineral sunscreen: PG McCormick, Adapting SPF testing methods for mineral sunscreen density, *Cosmetics & Toiletries* **2011**, *164*.

If you like my videos, you can also check out the rest on my YouTube channel or browse my videos tag if you prefer to read the more detailed version as well!

*Paper tape was a press sample I got at a media event. This post contains affiliate links – if you decide to click through and support Lab Muffin financially (at no extra cost to you), thank you! For more information, see Disclosure Policy.*

This post was very helpful. I’ve been using way too much sunscreen—about 1 1/2 tablespoons for my face, neck, chest, and ears. Now I understand why facial sunscreen is in such small bottles.

Your skin must’ve felt fantastically protected!

It was oddly satisfying watching you tape your face up like that haha. I’m so bad at measuring the sunscreen I put on my face. I tried a couple times and just got impatient, and figured at least I’m applying it which is better than nothing… right? I should probably measure it out properly one day and then work out how to eyeball it.

It was satisfying to do!

I think it’s a good idea to measure the first time, dump it onto your hand, then eyeball it, and repeat every few months to recalibrate your estimate.

Today is the day I measure my sunscreen! Only a month later…

Hahaha! Measuring sunscreen is always a bit scary – it’s always more than you think you need!

What a great post – you’re delightful to watch and who else would have every taped up their face to get as-close-as-you-can accurate measurements! I realized I’ve been overusing too (better than under utilizing), but knowing I can use a bit less will be a definite help to my always oily skin!

Thanks! I’m glad you enjoyed it!

Your face may be larger than mine so keep that in mind 😉

I always thought you needed more, 1/4 teaspoon is actually pretty little. Anyway, covering your face like that and doing the maths is one of the nerdiest things I have seen in a long time – I love it!

I loved your video — so nerdy and charming as well as informative! Thanks!

Hi Michelle,

I generally plaster my face on with sunscreen proportional to the sunny-ness of the day! A pretty bad metric to apply a volume of sunscreen to your face but it kind of works.

The downside is that have the “gunkiness” of sunscreen to deal with.

I’d probably recommend measuring it out the first time regardless – there’s a study that found that most people only apply 25-50% of the recommended amount even when told to apply liberally! 🙁

Hi Michelle, thanks so much for this video 🙂 I love posts in which people measure their face and calculate how much sunscreen to use, they’re weirdly satisfying. Anyway, I was wondering if it’s OK to use a damp beauty blender (or sponge) to apply my foundation after sunscreen? I’m wondering if the water on the sponge can mess up the sunscreen somehow? I do wait ~10 minutes after applying SPF to do my makeup btw.

Hello Jen, I do exactly the same, I use a damp sponge to gently pat my B.B. cream on top of the sunscreen after about 15min. I hope it’s a good thing we’re doing here?

We could use an advice from Michelle here…

Hi Michelle!

Wow, this was really cool. Thanks for taking the time to calculate it out, particularly for the comparison to 1/4 teaspoon. I definitely apply more than that and I think our faces are similar in size. It’s nice having this as a reference point as I rarely, if ever, actually measure out a quarter teaspoon. Perhaps I’ll be able to cut down on some of the grease now!

Woop! I just used this method for my face, but used strips of paper towel that I made wet (to stick to my face) instead. Being aware that the paper towel expands when wet, I did two measurements – one a simple calculation based on the area of the strips when dry, and one a direct measurement after laying the wet paper towel strips down after covering my face.

Dry measurement: 327.6 cm^2

Wet measurement: 351.36 cm^2

Based on these measurements, it looks like for my face alone, 1/8 teaspoon is enough for me, since my face is half the surface area that would require a 1/4 teaspoon to get the recommended thickness! (and that’s good to know, since I use more expensive sunscreen on my face, and then less expensive sunscreen with whitecast on my neck, décolletage, and body)

Thank you, this was a fun (and money-saving) way to spend a Saturday afternoon