What is the difference between skin tone and undertone?

Skin tone is the surface colour, which is mostly depth and changes with sun exposure. Undertone is the constant cast underneath it, warm, cool or neutral, and it does not change. Foundation matching needs both: the right depth and the right undertone.

Can your undertone change?

No. Your surface colour changes with a tan, with the weather and with age, but the underlying cast stays the same. If a color suited you at twenty and does not now, the likelier explanation is that your hair depth changed, not your undertone.

Can you be both warm and cool?

You can be neutral, which is the balanced case and is common. What you cannot be is warm on one measure and cool on another in any stable way; if your tests disagree, that is usually the signature of a neutral undertone rather than a contradiction.

Does undertone depend on race or ethnicity?

No. All three undertones occur in every ethnic group and at every skin depth. Averages differ between populations, but an average is useless for an individual, which is why the tests look at your skin rather than at a category.

Skin Undertone: What It Is and How to Find Yours

Your undertone is the constant colour underneath your skin, and it comes in three versions: warm (yellow or golden based), cool (blue or pink based) and neutral (a mix, or red based). It is not the same thing as how light or deep your skin is, it does not change with a tan, and it is the single most useful fact about your coloring when you are choosing a foundation, a metal or a white shirt.

Last updated August 2026 · Michael Machatschek

Undertone is not skin depth

This is the confusion that ruins most self assessments, and a lot of published advice makes it worse. Depth is how much melanin you have: how light or deep your skin appears. Undertone is the colour cast underneath it. They are independent.

A very fair person can be warm and a very deep person can be cool. Both are common. Any rule that maps deeper skin onto warm undertones, or fair skin onto cool, is describing an average rather than a mechanism, and it will be wrong for a large share of people. The whole point of measuring undertone separately is that you cannot read it off depth.

What causes it

Skin colour comes mostly from two pigments. Melanin runs yellow to brown to nearly black and controls depth. Haemoglobin in the capillaries under the skin runs red to blue and shows through more in thinner or less pigmented skin.

Undertone is roughly the balance of those two once depth is accounted for: more yellow relative to red and blue reads as warm, more blue and pink reads as cool, and a balance of the two reads as neutral. This is why undertone is stable while your surface colour changes with sun, temperature and season.

None of this is folklore. Skin colour has been measured in exactly these coordinates since Chardon and colleagues introduced the Individual Typology Angle in 1991, which classifies skin from its CIELAB lightness and yellowness. What color analysis adds is not the measurement, it is the decision about what to wear against it.

The quickest reliable check

Two fabrics, daylight, no makeup. Hold pure white under your chin, then ivory or cream. Look at the skin under your eyes and around your mouth rather than at the fabric. Warm skin looks healthier and more even against ivory; cool skin looks clearer against pure white. If neither changes much, you are probably neutral, and neutral is a real answer rather than a failure to decide.

Questions people ask

What is the difference between skin tone and undertone?: Skin tone is the surface colour, which is mostly depth and changes with sun exposure. Undertone is the constant cast underneath it, warm, cool or neutral, and it does not change. Foundation matching needs both: the right depth and the right undertone.
Can your undertone change?: No. Your surface colour changes with a tan, with the weather and with age, but the underlying cast stays the same. If a color suited you at twenty and does not now, the likelier explanation is that your hair depth changed, not your undertone.
Can you be both warm and cool?: You can be neutral, which is the balanced case and is common. What you cannot be is warm on one measure and cool on another in any stable way; if your tests disagree, that is usually the signature of a neutral undertone rather than a contradiction.
Does undertone depend on race or ethnicity?: No. All three undertones occur in every ethnic group and at every skin depth. Averages differ between populations, but an average is useless for an individual, which is why the tests look at your skin rather than at a category.

Sources

[1]

Chardon, A., Cretois, I., & Hourseau, C. (1991). Skin colour typology and suntanning pathways. International Journal of Cosmetic Science, 13(4), 191-208.

Introduced the Individual Typology Angle, which classifies skin colour from CIELAB lightness and yellowness. Skin colour has been measurable in exactly the coordinate space this tool uses since 1991.
[2]

Kienle, A., Lilge, L., Vitkin, I. A., Patterson, M. S., Wilson, B. C., Hibst, R., & Steiner, R. (1996). Why do veins appear blue? A new look at an old question. Applied Optics, 35(7), 1151-1160.

Vein colour is produced by how skin scatters and absorbs light at different wavelengths, together with vessel depth and diameter, not by the colour of the blood. It is an optical effect of the tissue above the vessel.
[3]

Fitzpatrick, T. B. (1988). The validity and practicality of sun-reactive skin types I through VI. Archives of Dermatology, 124(6), 869-871.

The burn-or-tan scale was devised in 1975 to pick starting UVA doses for psoriasis phototherapy in white skin. It measures how skin reacts to ultraviolet light, which is a melanin question, and it was never a measure of undertone.

Not sure which season you are?

The test measures all three dimensions and gives you a season, the reasoning and the full palette. It takes about a minute and needs no account.

Take the 60 second test