Undertone Test
Skin Undertone Test: Warm, Cool, or Neutral?
Your undertone is the subtle colour cast beneath your skin's surface — and it decides whether gold or silver, warm or cool colours flatter you. Here's how people test it by hand, why those methods are unreliable, and how to measure it from a photo instead.
- Warm
Skin leans golden or yellow. Gold jewellery, earth tones, and warm reds flatter.
- Cool
Skin leans pink or blue. Silver jewellery, blues, and berry shades flatter.
- Neutral
Neither cast dominates — both warm and cool palettes can work.
The classic self-tests — and their limits
The vein test. Look at the veins on your inner wrist in daylight: greenish veins suggest a warm undertone, bluish or purple veins suggest cool, and a mix suggests neutral. The catch: vein colour also depends on how deep the vessels sit and how thick your skin is, and it becomes genuinely hard to read on tan and deep skin.
The jewellery test. If gold jewellery makes your skin glow and silver looks flat, you probably lean warm; if silver flatters and gold looks brassy, you lean cool. Honest limitation: this is a judgement call about your own face, and most of us are biased by what we already own.
The white-cloth test. Hold a pure white cloth beside your bare face in daylight. Skin that looks yellowish next to it leans warm; pinkish leans cool. Indoor bulbs and even a white wall's reflection can flip the reading.
These folk methods are a reasonable starting point, but they all rely on eyeballing subtle colour differences under uncontrolled lighting — precisely what human eyes are bad at.
The 30-second photo test
MoonSkin measures undertone instead of asking you to judge it. A live quality gate in your browser checks that your face is detected, well lit, sharp, and centered. Then your cheeks, forehead, and jaw are sampled pixel by pixel, converted to the Lab colour space, and the a/b colour axes — how red-green and yellow-blue your skin actually is — decide Warm, Cool, or Neutral. Lighting is normalised first, so a warm bulb doesn't masquerade as a warm undertone. You also get your skin tone depth, natural base, best dress colours, and a skincare routine in the same free report.
Take the 30-second photo testUndertone FAQ
How do I know my skin undertone?
Traditional self-tests look at your veins (greenish suggests warm, bluish suggests cool), which jewellery flatters you (gold for warm, silver for cool), or how white fabric sits against your face. These are rough heuristics — lighting and skin depth easily skew them. A measured alternative is a photo analysis: MoonSkin computes your undertone from facial skin pixels in the Lab colour space, free and in about 30 seconds.
What are the three undertones?
Warm (skin leans golden or yellow), Cool (skin leans pink or blue), and Neutral (no dominant cast). Undertone is independent of how light or deep your skin is — every undertone occurs at every depth.
Is the vein test accurate?
Only loosely. Vein colour depends on vessel depth, skin thickness, and lighting as much as on undertone, and it gets harder to read on deeper skin tones. Treat it as a hint, not a verdict — if your veins look ambiguous, that alone doesn't make you neutral.
Why does undertone matter?
It drives which colour families flatter you: warm undertones harmonise with earth tones, golds, and warm reds; cool undertones with blues, berries, and silver; neutral undertones can borrow from both. It's also the single most useful fact when choosing foundation shades and jewellery metals.
MoonSkin provides cosmetic and styling guidance, not medical advice. For any skin health concern, please consult a qualified dermatologist.