You know that moment when you buy foundation and it looks perfect in the store, but the second you step outside you're wearing a literal mask? Yeah, that's not the lighting's fault — it's probably your undertones laughing at you.

Undertones are the reason foundation matching feels like advanced chemistry. But once you understand yours, the whole process clicks. No more orange jawlines. No more gray faces. Just skin that looks like… your skin.

What Are Undertones, Actually?

Your undertone is the subtle color underneath your skin's surface. It's not about how light or dark you are — that's your skin tone. Undertones are the vibe underneath: warm (yellow/golden), cool (pink/rosy), or neutral (a mix of both).

Think of it like this: two people can have the exact same shade of beige skin, but one looks best in gold jewelry and warm browns, while the other glows in silver and cool pinks. That's undertones doing their thing.

The three undertone categories:

• Warm: Yellow, golden, peachy base

• Cool: Pink, red, bluish base

• Neutral: A balanced mix — you can pull off both warm and cool shades

Most people land firmly in one camp, but some lucky neutrals exist in the middle. And yeah, you can be deep-toned with cool undertones, or pale with warm undertones. Undertone and skin tone are not the same thing.

How to Figure Out Your Undertone (Without Buying Ten Foundations)

There are a million TikTok tricks for this, and honestly? Some of them work. Here are the ones that actually hold up:

1. The Vein Test

Look at the veins on your wrist in natural light.

• Green veins = warm undertones

• Blue or purple veins = cool undertones

• Can't tell / both = probably neutral

This one's fast and surprisingly reliable. Just make sure you're checking in daylight — indoor lighting will lie to you.

2. The Jewelry Test

Do you look better in gold or silver jewelry?

• Gold = warm undertones

• Silver = cool undertones

• Both look good = neutral

If you've ever bought a necklace and felt like it just… didn't vibe with your skin, this is why.

3. The White T-Shirt Test

Hold a pure white shirt (not cream, not off-white — actual white) next to your face in natural light.

• If your skin looks yellowish or golden, you're warm

• If it looks pink or rosy, you're cool

• If it looks pretty balanced, you're neutral

This one's weirdly accurate but requires good lighting. Bathroom fluorescents will sabotage you.

4. The Tan Test

How does your skin react to sun?

• If you tan easily and turn golden or olive, you're likely warm

• If you burn first and tan reluctantly, you're likely cool

• If you do a bit of both, you might be neutral

Obviously, this isn't foolproof (sun damage isn't a personality quiz), but it's a decent clue.

Why Undertones Matter for Foundation

Here's the thing: if you ignore undertones, your foundation will always look a little… off. Not catastrophically bad, just not quite right. Like it's sitting on top of your skin instead of melting into it.

Warm undertones need foundations with yellow or golden bases. If you go too pink, you'll look washed out or ashy.

Cool undertones need foundations with pink or rosy bases. Too much yellow and you'll look weirdly jaundiced.

Neutral undertones have the most flexibility, but you still want to avoid extremes. Stick to balanced shades that don't lean too hard in either direction.

And here's where things get tricky: most foundation shade names don't tell you the undertone. "Sand" could be warm or cool depending on the brand. "Beige" means nothing. You're just supposed to… know? Or swatch seventeen shades in-store and hope for the best.

The Old Way vs. the Better Way

The traditional advice is to swatch three shades on your jawline in natural light, wait 30 seconds for oxidation, and pick the one that disappears. Which is fine, except:

• You need access to testers (not always available)

• Store lighting is designed to lie to you

• Oxidation takes longer than 30 seconds for some formulas

• You're guessing based on a tiny stripe of product

This is why people end up with a drawer full of "close enough" foundations that are all slightly wrong.

Virtual try-on tools like Blioh solve this by letting you see how shades look on your actual face, in your actual lighting, without committing to anything. You can test warm vs. cool undertones instantly and figure out which direction your skin leans without buying a single bottle.

What About Olive Undertones?

Okay, so olive is technically a mix of warm (yellow) and cool (green), but it's subtle enough that it deserves its own mention. If you're olive, you probably:

• Look slightly gray or green in bad foundation

• Can't figure out if you're warm or cool (because you're neither)

• Look amazing in earth tones and jewel tones

Olive undertones are more common in Mediterranean, Middle Eastern, and South Asian skin, but they show up across all ethnicities. The key is finding foundations with a slightly muted, greenish-yellow base instead of pure warm or cool.

Common Undertone Mistakes

Assuming undertone = skin tone

You can be pale and warm. You can be deep and cool. They're separate.

Matching foundation to your hand instead of your face

Your hands are often a different tone than your face. Always match to your jawline or neck.

Ignoring seasonal shifts

Some people's undertones shift slightly with sun exposure. If you tan in summer, you might need a warmer shade than you do in winter.

Trusting one test

If the vein test says warm but the jewelry test says cool, try a neutral shade. No single test is gospel.

How Blioh Helps You Skip the Guesswork

Instead of playing detective with veins and t-shirts, you can just… try shades on. Blioh's virtual try-on lets you see how different undertones look on your actual skin in real time. Warm too orange? Try cool. Cool too pink? Shift warmer. You'll know instantly which direction feels right.

And because Blioh shows you shades from hundreds of brands, you're not locked into one formula or shade range. You can test Fenty, NARS, Maybelline, whatever — all without leaving your house or touching a single tester.

Quick Recap

• Warm undertones: Yellow, golden, peachy base. Look for foundations with "W" or "warm" in the name (or yellow-based shades)

• Cool undertones: Pink, rosy, bluish base. Look for "C" or "cool" or pink-based shades

• Neutral undertones: Balanced mix. Look for "N" or "neutral" or shades that don't lean too hard either way

• Olive undertones: Muted green-yellow mix. Look for foundations with a slightly greenish or muted base

Figure out your undertone once, and foundation shopping becomes 10x easier. You'll stop buying the wrong shades. You'll stop looking like you're wearing a mask. You'll just… match.

And if you're still not sure? Try a few shades virtually. See which one makes you go "oh, that's my color." That's the one.

FAQ

Can your undertone change over time?
Nope. Your undertone is fixed — it's determined by melanin and hemoglobin in your skin. What can change is your skin tone (how light or dark you are), which shifts with sun exposure, but the undertone underneath stays the same.

What if I still can't tell if I'm warm or cool?
You might be neutral, which means you're balanced between the two. Neutral undertones have the most flexibility with foundation shades, but you'll still want to avoid extreme warm or cool formulas.

Do I need different foundations for summer and winter?
If you tan significantly, yes. Your undertone stays the same, but your depth changes, so you'll need a darker shade in summer. If you don't tan much, you can stick with the same shade year-round.

Can two people with the same undertone wear the same foundation?
Not necessarily. Undertone is just one factor — you also need to match depth (how light or dark you are). Two people with cool undertones could need completely different shades depending on their skin tone.