Notes

What is skin undertone, and how do you find yours?

Last updated: 22 August 2026

Undertone is the hue under your skin's surface: cool, warm, neutral or olive. A white cloth against a cream one, in daylight, finds yours.

Undertone is the hue underneath your skin, produced by melanin in the epidermis and haemoglobin in the vessels below it. It reads as cool, warm, neutral or olive, and it holds steady while your surface colour moves with sun and irritation. The best test you can run without buying anything is a white cloth against a cream cloth, in daylight, on a bare face.

Undertone, overtone and depth are three different things

Almost every argument about undertone is a confusion between three separate properties.

Depth is how light or dark your skin is, and it shifts more than anything else across a year.

Overtone is the colour on your surface right now: a tan, the redness after a run, the flush of rosacea, the mark a spot leaves behind. It is temporary and often uneven.

Undertone is the hue beneath both. It comes from pigment sitting inside your skin instead of on it, which is why you cannot wash it off and why it stays put.

Does your undertone change when you tan?

Not enough to matter. Tanning is your skin making more melanin, which moves your depth and, for a while, your overtone. The balance of hues underneath shifts far less, and slowly enough that your shade family holds across a season.

Most people therefore need two foundation shades a year in the same undertone family. If your winter shade is 2N and you buy 4W in July because it looks closer on the back of your hand, you have fixed depth by breaking undertone, and it reads orange along the jaw.

What is an olive undertone?

Olive is an undertone, and the one most shade ranges get wrong. It is a green or grey cast that can sit at any depth, from very fair to deep, and it is not a midpoint between warm and cool. A shade code with only cool, neutral and warm letters has nowhere to put you, so ranges match olive skin to a shade correct in depth that then reads pink or orange on the face. If white cloth makes you look faintly grey, not yellow and not pink, olive is the likely answer.

The home tests, and what each one is really measuring

Every popular test is a proxy for something you cannot see directly, and the most famous one is the worst. The trust column below is Looksmith's own ranking, graded on one thing: how much of the answer comes from your skin instead of from your lighting, your skin thickness or your taste.

Does the vein test work?

No, and the physics explains why. Veins carry dark red deoxygenated blood, so their apparent colour is an optical effect. It is not the colour of the vessel. Kienle and colleagues took this apart in Applied Optics in 1996, in a paper titled "Why do veins appear blue? A new look at an old question." They found four things set that colour at once: how skin scatters and absorbs each wavelength, how oxygenated the blood is, how wide and deep the vessel is, and how the visual system reads the contrast.

So vein colour depends on the vessel and on what the tissue above it does to light. Thin fair skin over a shallow vein reads blue. Thicker skin, or skin with more melanin in it, more often reads green. Two people with the same undertone get different answers, and one person gets two under a warm bulb and at a window. The test survives because it is quick and it feels like evidence. Treat it as the least informative thing in the table.

What is the white versus cream test?

Take a piece of pure white cloth, a plain t-shirt or a sheet, and a piece of cream cloth of similar weight. With no makeup on and hair tied back, hold each under your chin in turn.

Cool skin looks cleaner against pure white and dull or yellowed against cream. Warm skin looks clearer against cream and grey against pure white. Neutral skin looks fine against both, which is a real answer and not a failed test. Olive skin reads green against both, and greener against white.

Does the gold or silver test work?

Less than people claim, and never on its own. Metal near your face bounces light back at it, so gold pushes a warm cast onto your skin and silver a cool one. Which one sits closer to your own hue depends on undertone, but also on your depth and on the contrast between your skin, hair and eyes. Plenty of cool-toned people wear gold well, so use this to break a tie between two readings, not to produce a reading of its own.

Does lighting affect your undertone test?

Lighting affects the answer more than the choice of test does. A warm household bulb sits near 2700 K, a cool white bulb near 4000 K, and overcast daylight around 6500 K. Shop lighting is generally warmer than daylight, and it is set for how the products look, not for how your skin reads.

Test at a window in indirect daylight, in the middle of the day. That one change improves your answer more than picking a better test. Do not use a selfie as your reference either: your phone's automatic white balance neutralises the exact cast you are trying to measure.

How to find your undertone at a window

1. Remove your makeup and wait for any redness from cleansing to settle.
2. Tie your hair back and take off any metal near your face.
3. Stand at a window in indirect daylight.
4. Hold white under your chin, then cream, then white again. Note which makes your skin look clearer, not which you prefer.
5. Compare your inner upper arm to your forearm. The covered skin is closer to your baseline.
6. Repeat on another day. Two answers that agree are a result.

What undertone actually decides

Undertone decides two things: your foundation match, and which family of lipsticks is worth trying. That short list is worth more than the long one people usually give you.

How does undertone change which foundation you buy?

The letter, not the number. Most ranges split a shade code into depth and undertone, commonly N for neutral, C or P for cool and pink, W or G for warm and golden. No standard governs those letters, so brands use them differently, and MAC is the classic trap. MAC's own shade finder defines NC as Neutral Cool for golden skin and NW as Neutral Warm for rosy skin, and notes on the same page that other brands tend to define cool and warm as the opposite. Golden skin belongs in an NC number at MAC and in a W number in most other ranges. Read the brand's own definition before you trust its letter.

Getting the letter wrong is the most visible mistake in base makeup. A shade one step too light or too dark blends out. A shade in the wrong undertone family does not, because a hue mismatch has no edge to blend into the way a brightness mismatch does, and it shows as a grey, pink or orange line along the jaw in daylight. Allow for oxidation too. The stripe you judge at minute ten is a different colour from the stripe you drew, so wait before you decide.

Which lipsticks does undertone rule out?

Undertone decides which family of reds reads as intentional on you. Warm undertones carry orange-based reds, brick and coral. Cool undertones carry blue-based reds, berry and true rose. Neutral undertones go either way and should choose on depth instead. A blue-based red is also the standard advice for making teeth look whiter, on the reasoning that it changes what your eye compares your teeth to. Treat that as a rule of thumb, not a measured effect.

The effect is real, but smaller than the internet insists, and opacity decides how much it matters. A sheer wash of a wrong-family shade usually looks fine. A full-coverage matte in that same family is the one that looks off.

What undertone does not decide

Undertone gets credited with nearly everything and deserves almost none of it. It does not decide whether you can wear black or white, what colour your blush should be, or which of twelve seasons you belong to. It is one input into hair colour, not the answer.

Those calls depend more on depth and on contrast, meaning the gap between your skin, hair and eyes. The usual advice is that a high-contrast face carries a strong lip more easily than a low-contrast one. Whether that holds for you is something you can see, and no wrist test measures it.

If someone hands you a fifty-item list of forbidden colours derived from one vein reading, the list is not built on anything. The cool, warm or neutral question has a page of its own: cool, warm or neutral.

Seeing it beats deducing it

Undertone is a shortcut. You reason from a proxy because you cannot see the lipstick on your face until you have bought the lipstick. When you can see the thing itself, the shortcut matters less.

Looksmith skips the proxy. You save a Likeness once, a set of selfies that becomes your reusable face, then pick a look, and Looksmith renders that complete look onto your own face and lists the products it used beside it. Looksmith works on your own photograph, not a model's, so your pose and framing stay as they are, and it will not reshape your face. Looksmith moves skin tone by at most one step, through product finish.

Looksmith does not measure your undertone or tell you what it is. It shows you a finished look on your face, which is a different question. Looksmith is coming soon to iOS from Mirable Labs, Inc., and is not released yet. Looksmith grants the first six looks free at onboarding, and after that it runs on credits bought in packs, with no subscription.

A Looksmith look shows you how makeup sits on your face. A foundation stripe along your jaw in daylight, judged after ten minutes, tells you what your skin is. If you do one thing this week, do the second.