The Most Flattering Hair Colours for Cool Skin Undertones

You could follow every TikTok hair colour trend and book the best colourist, but if the shade doesn’t suit your undertone, it’ll still fall flat. The right hue, on the other hand, lights you up.

The secret? It’s all in your undertone. When your hair colour complements your skin’s natural tone, everything clicks — you look more radiant, balanced, and effortlessly cool.

If you’ve got a cool undertone, you’re in luck. We’ve rounded up the most flattering shades just for you. But first, let’s talk undertones.

What Is A Skin Undertone?

Think of your skin like your favourite Instagram filter – it has a base layer that sets the whole mood, even if you don’t always notice it. The base layer is your skin undertone – the subtle, underlying hue beneath the surface of your skin.

Unlike your skin tone, which changes with sun exposure, makeup or lighting, your undertone is always there and it doesn’t change. It’s like the secret foundation that gives your complexion its natural glow and helps you pick colours (like hair dye, clothes and makeup) that make you look flawless.

There are four main undertones:

• Cool – pink, red, or bluish
• Warm – golden, yellow or peachy
• Neutral – a mix of cool and warm, balanced perfectly
• Olive – a mix of neutral and green/grey tones

Knowing your undertone is like having a personal colour code – once you crack it, choosing hair colours that make you shine becomes a breeze.

How to Find Your Skin Undertone

Not sure what your skin undertone is? No stress – you can easily figure it out with a few quick checks (no glam squad required). Start with the vein test by looking at the veins on the inside of your wrist.

If they appear blue or purple, you’re likely cool-toned. If they look green, you’re probably warm-toned. If it’s hard to tell or seems like a mix, you might be neutral.

Another easy one is the jewellery test. If silver jewellery tends to look better on you than gold, that’s a strong sign you’re in the cool undertone club. And if gold jewellery tends to look better than silver, you’re in the warm undertone club.

Lastly, there’s the sun test. If you burn more easily than you tan, chances are you’re cool-toned, whereas frequent tanners usually lean warm. Still unsure? You could likely be a neutral, or even olive, which has a slightly green-grey cast and doesn’t always fit neatly into warm or cool categories.

Once you’ve got your undertone figured out, you’re ready to pick hair colours that actually work with your skin – not against it.

Best Hair Colours for Cool Undertones

Cool Dark Brown

Classic, rich, and endlessly chic – cool dark brown is one of the most flattering shades for cool undertones. This hue has an ashy base with zero warm or golden highlights, which means it complements your skin without clashing any redness or pinkness.

Think espresso, dark chocolate, or iced coffee – all the deep, cool vibes with none of the brassiness.

It’s perfect if you want something low-maintenance but still high-impact, adding depth and dimension to your hair while keeping things sleek and natural.

Mushroom Brown

Don’t let the name fool you. Mushroom brown is way more stylish than anything you’d find on a pizza. This earthy, smoky shade is a mix of ashy brown, taupe, and soft grey tones, giving it a cool-toned, dimensional finish that flatters just about every cool undertone out there.

What makes this colour so magical is its versatility – it works on both light and medium-dark hair, adds a natural softness to your features, and gives your skin that subtle lit-from-within glow. Perfect if you want something modern and understated, without committing to something too bold or too basic.

It also grows out beautifully, making it a smart pick for anyone who doesn’t want to be in the salon every six weeks.

Deep Plum

If you’re ready to dip your toes – or your roots – into something a little more daring, deep plum is the perfect pop of colour for cool undertones. This rich, sultry shade blends dark brown or black with hints of violet and eggplant, creating a multidimensional, jewel-toned finish that sings on cool skin.

Plum works especially well because purple is naturally a cool colour that enhances the pink, red, or blue undertones in your skin rather than competing with them. It creates a gorgeous contrast that brings out the brightness in your complexion and makes your features look sharper and more defined.

Burgundy

Burgundy is bold, elegant, and just the right amount of moody.

Unlike warmer reds, which can clash with cool undertones, burgundy leans into violet and berry hues that complement pink, red, or blue undertones in the skin. The result is a striking contrast that makes your skin look more luminous and balanced.

Whether you’re aiming for a full burgundy transformation or subtle wine-tinted highlights, it’s a colour that turns heads while still feeling polished.

Blue-Black

Blue-black is the ultimate cool-toned hair colour if you’re after something sleek, mysterious, and undeniably striking.

This shade combines the depth of black with a subtle hint of blue undertones – giving it a glossy, multidimensional finish that flatters cool undertones perfectly. The blue tint neutralises any redness or pinkness in the skin, making your complexion appear clearer and your features sharper.

Unlike harsh jet black, the blue-black tone adds a modern edge and softens the overall look, keeping it sophisticated yet fashion-forward. It’s a great choice if you want something timeless but with just a little extra personality.

Ash Blonde

Ash blonde is the perfect icy, cool-toned blonde for those with cool undertones looking to brighten their look without adding warmth. This shade features soft, smoky beige and grey undertones that avoid any golden or yellow hues, making it ideal for balancing out pink or rosy skin tones.

The coolness of ash blonde creates a beautiful contrast that makes your skin look luminous and fresh, while giving your hair a light, airy feel. It’s a great choice if you want to switch things up with something bright and chic, but still perfectly in sync with your natural undertones.