Deciding between blonde, brunette, and red is tough enough without considering the spectrum of tones that exist within those hues. And then you have to think about how those shades work with your complexion? (Can we take a nap now?)
But understanding the nuances of tone can actually make the difference between choosing a good hair colour and your most flattering one ever—and with a little crash course, it's actually not that hard to figure out. "It's all about placement, saturation, and what undertones in your skin you'd like to emphasise," says Roxie Darling, colouring guru at New York City's Hairstory. "The decision you and your colourists have to make is which colour you would like to bring out in your face."
But it helps when you have a basic knowledge of what cool vs. warm hair shades actually look like as well as an understanding of your skin's colouring to begin with. Consider this your foolproof guide to all of the above.
Before taking your pick of hair colours, you need to ID your skin's undertones. Most people fall into one of three categories: warm, cool, and neutral. Figuring out where your complexion lies can seem confusing, but there are a few tricks:
1. Look for specific colours. "Cool-toned skin has pink and olive undertones while warm-toned skin has yellow and gold," says Rachel Bodt, senior colourist at Cutler Salon. Got a combo of any of the above? You're probably neutral.
2. Match yourself with a celeb. When you're looking for A-list colour inspiration, try to pick out people with similar skin and eye colouring to your own. It will give you a much better idea of how the hue will actually look on you in the end.
3. Check your wrist… "You'll see the pinks, reds, blues, greens, and yellows there," says Darling. This includes your veins, which are a great indicator of tone. "If your veins are blue or purple, you're likely cool-toned," says Bodt. "If they are green, you are warm."
4. …Or your eyes. "If you have a lot of gold specks in your eyes, usually your undertones are warm," says Matrix celebrity stylist George Papanikolas, who works with the Kardashians and Miranda Kerr. "If you have a lot of blues and greens, then you are usually cool."
The rule of thumb for a hair colour that will flatter your complexion: Pick a tone that's opposite from your skin's undertones. So, those with warm undertones might opt for a cooler colour, and vice versa. The degree to which this matters varies from hair colour to hair colour, but it's a good guideline to remember. And if you have neutral skin, you're a lucky minority—everything looks good on you.
Now that you're well versed on your skin colouring, it's time to get schooled on different hair colours.
Pictured: Hanne Gaby Odiele
Shades: Platinum, ice, silver, ash, sand, beige, champagne
Who it's best for: Cool blonde shades are great on porcelain-skinned gals with reddish undertones, since those icy hues tend to neutralise redness, says Chelsey Pickthorn, Davines colour educator and owner of Pickthorn Salon in Brooklyn. "If you have blue or grey eyes, cool, ashy blondes work well," adds Daniel Sanchez, who works with Karlie Kloss.
Your must-have product: Pureology Perfect 4 Platinum Conditioner (£17)
Pictured: Rosie Huntington-Whiteley
Shades: Gold, caramel, amber, honey, butterscotch
Who it's best for: "Fair skin with cool undertones looks better with warm tones: strawberry blondes, copper, honey, and gold," says Papanikolas. He also notes that these hues tend to be better for those with olive skin, as ashy blondes can wash you out. Same goes for those with deep skin: If you want to go light, Sanchez recommends a caramel blonde for a high-impact look.
On the other hand, those with very warm skin should avoid a colour that's too yellow for the same reason—cooler blondes will probably work better on you.
Your must-have product: Rita Hazan Ultimate Shine Gloss in Blonde (£21)
Seen on: Ali Larter
Shades include: True red, dark auburn, burgundy
Who it's best for: It may sound counterintuitive, but red is actually a very flattering option for those with ruddy undertones. "If you have pale skin with red in it, it makes you have a glow rather than trying to fight it," says Rita Hazan, Beyoncé's go-to pro. Those with warm, peachy complexions will also see their skin pop with cooler, auburn reds, says Pickthorn.
On the other hand, Hazan cautions those with olive undertones against going red, as it can make skin look very green in contrast.
Your must-have product: Davines Alchemic Red Shampoo (£16)
Pictured: Miranda Kerr
Shades: Dark chocolate, chestnut, dark auburn, mocha
Who it's best for: It's pretty hard to go wrong with brown in general, since it's almost universally flattering. But cooler tones can look particularly striking on those with warm skin, as it helps make yellow undertones look more creamy. Sanchez also adds that for girls with deeper skin, lightening from black to deep, mocha brown (ideally with multi-tonal highlights) can have a gorgeous, soft effect.
Your must-have product: Bb Colour Gloss in Brunette (£26)
Pictured: Jessica Chastain
Shades: Strawberry blonde, copper, amber, rust, russet
Who it's best for: "Strawberry blonds are great on fair and neutral skin tones," says Pickthorn, who instructs to tell your colorist to "mix cool and warm tones to achieve a creamy yet warm colour with a hint of golden copper." Papanikolas also recommends a light, warm red to counteract cool tones in pale skin (think Emma Stone). These hues tend to make deep skin look green, so choose a cooler, brown-tinged auburn instead if you're hankering to go red (think Rihanna).
Your must-have product: John Frieda Radiant Red Boosting Conditioner (£7)
Pictured: Emilia Clarke
Shades: Caramel, honey, golden brown, amber, mahogany, cinnamon
Who it's best for: Sanchez especially recommends this color range for those with medium skin, though he advises picking a shade that contrasts with your complexion in order to avoid looking washed out. "Caramel browns fit best with skin tones on the lighter side of olive, with a bit more yellow and green tones to them," adds Pickthorn. "This colour looks really beautiful on a base or roots that are naturally dark."
Your must-have product: Ghd Final Shine Spray (£10)
Pictured: Bella Hadid
Shades: True black, espresso, blue-black, licorice
Who it's best for: In the world of hair color, black isn't a one-note option—different tones and highlights add subtle variety. A cooler shade like this can read a little harsh on those with fair, cool-toned skin, but for those with warmer or neutral undertones, it has a dramatic, porcelain effect on the complexion. (The same applies to olive skin.)
Your must-have product: Maria Nila Colour Refresh Black (£16)
Pictured: Joan Smalls
Shades: Dark mocha, brown-black
Who it's best for: Cool blacks look great on deep skin, but adding chocolaty tones is also a flattering way to warm it up. And those with fair, cool skin who really want to go dark should opt for a hue in this tonal range rather than something cooler, as mentioned before.
Your must-have product: Shea Moisture Black Castor Oil Mask (£11)
Pictured: Irene Kim
Shades: Whatever your heart desires
Who it's best for: For rainbow-coloured hair, the only real rule is to let your imagination run wild. That being said, there are some pointers to keep in mind. "Darker skin tends to look washed out if paired with paler shades, while saturated hues enhance deeper skin tones," says Darling, who specialises in creative colour. "So for tan skin, you can go for more vibrant and saturated tones: Jewel tones like ruby, fuchsia, magenta, etc." She adds that blue hair looks particularly flattering on those with golden complexions. But the most important thing to remember about candy-coloured hues: They tend to fade fast, so make sure you're using colour-protecting products to extend that shelf life as long as possible.
Your must-have product: Bleach London Reincarnation Mask (£6)
This post originally appeared on Byrdie U.S. and has since been updated.