You’re staring at a box of dye or a professional swatch book. There are numbers like 7.32 or 5.1 or 10.02 staring back at you. Honestly, it looks more like a high school algebra quiz than a beauty product. Most people just look at the picture on the front of the box or the hair sample in the book and pray. But those photos? They’re often lying to you. Lighting, Photoshop, and the model's original base tone make those images basically useless for predicting what will happen on your own head.
If you want to stop guessing, you have to learn the secret language of hairdressing colour chart numbers. It’s the universal system used by brands like L'Oréal, Wella, and Schwarzkopf. Once you crack the code, you’ll realize that the first number tells you how dark it is, while the numbers after the dot tell you the "flavour" or the tone. It’s the difference between ending up with a sophisticated mushroom blonde or looking like a literal pumpkin.
The First Digit: How Light Are We Talking?
The very first number in the sequence is the Level. This is the most important part of the hairdressing colour chart numbers system. It’s a scale from 1 to 10. 1 is the darkest black imaginable. 10 is the lightest, palest blonde. Some brands like Goldwell or Matrix might throw in an 11 or 12 for "high lift" blondes, but for the most part, we stick to the 1-10 range.
Think of it like a ladder. You can’t just jump from a Level 2 (Darkest Brown) to a Level 10 (Lightest Blonde) in one go without some serious chemical intervention (and probably some hair breakage). If you’re at a Level 5, which is a medium brown, and you pick a box that starts with a 7, you’re looking to go two shades lighter.
It sounds simple, but here is where people mess up. Natural hair has underlying pigments. When you lift hair (make it lighter), you expose warmth. If you are a Level 4 and you want to be a Level 7, you aren't just getting "blonde." You are fighting through a wall of red and orange pigment that lives inside your hair fibers. That is why the second half of the number matters so much.
Decoding the Tones: What Happens After the Dot
The numbers after the decimal point are the "Reflect." This is what gives the hair its character. Is it ashy? Is it golden? Is it iridescent?
While most professional brands use a similar system, there is a slight variation between "International" numbering and specific brand charts. Generally, though, the standard goes like this:
.0 is Natural. .1 is Ash (usually a blue or green base to kill orange). .2 is Iridescent or Violet. .3 is Gold. .4 is Copper. .5 is Mahogany. .6 is Red. .7 is Mat or Khaki.
So, if you see hairdressing colour chart numbers like 8.1, you are looking at a Light Blonde with an Ash tone. This is the holy grail for people who hate "brassiness." The blue/green in the .1 cancels out the orange that naturally pops up when you lighten hair to a Level 8. On the flip side, an 8.3 is a Light Golden Blonde. Same lightness, totally different vibe. One looks like cool moonlight; the other looks like a sun-kissed beach.
If there are two numbers after the dot, like 7.34, the first number is the primary tone and the second is the secondary tone. In 7.34, you have a Medium Blonde that is mostly Golden but has a hint of Copper. The first number after the dot always carries more weight. It's about 70% of the reflect, while the second number is the "shimmer" in the background.
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The Ghost of the Double Number
Sometimes you’ll see something like 6.66. No, it’s not a bad omen. In the world of hairdressing colour chart numbers, a doubled-up digit means intensity. A 6.6 is a Dark Blonde Red. A 6.66 is a Very Intense Dark Blonde Red. It means the manufacturer has packed more pigment into that tube to make the color scream.
Then there’s the "0" placement. This trips up even some junior stylists. If the zero comes before the tone, like 8.03, it means the tone is "sheer" or "natural-looking." It’s just a whisper of gold. But if the zero comes after, like 8.30, it usually means a more saturated, deep version of that gold.
Why Your Hair Doesn't Look Like the Swatch
You can follow the hairdressing colour chart numbers perfectly and still end up with a mess. Why? Because of the "Starting Canvas."
Hair color is subtractive and additive math. If you put a .1 (Ash) over hair that is already very "ashy" or porous, you might end up with hair that looks muddy or even slightly green. If you put a .3 (Gold) over hair that is already very orange, you’re basically doubling down on the warmth and heading toward a neon carrot situation.
Professional colorists use the "Color Wheel" to balance these numbers.
- Ash (.1) neutralizes Orange.
- Violet (.2) neutralizes Yellow.
- Green (.7) neutralizes Red.
If you have yellow-blonde hair and you want that "icy" look, you don't look for a .1 necessarily; you look for a .2 (Violet) because violet sits opposite yellow on the color wheel. Using an ash (.1/Blue) on yellow hair can sometimes result in a weird swamp-green tint because blue + yellow = green. Basics of art class, right?
Real-World Examples of Popular Combinations
Let’s look at some common hairdressing colour chart numbers you’ll see in high-end salons.
9.12 (Pearly Ash Blonde): This is a favorite for toners. The 9 is very light. The .1 (Ash) cuts the orange, and the .2 (Violet) cuts the yellow. It creates that "expensive" clean blonde that isn't too grey but definitely isn't yellow.
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5.5 (Mahogany Brown): The 5 is a classic medium-to-dark brown. The .5 is Mahogany, which is a mix of red and violet. It’s a cool-toned red. It doesn't look like a fire engine; it looks like a rich black cherry or a glass of Merlot.
4.0 (Natural Medium Brown): This is the baseline. No added tones. It’s used primarily for 100% grey coverage. Grey hair is stubborn. It lacks all pigment, so it needs the "Natural" (.0) series to fill it back up before you can even think about adding fancy tones.
The Mystery of Brand-Specific Letters
Just to make your life harder, some brands (looking at you, Redken and Goldwell) sometimes use letters instead of hairdressing colour chart numbers.
- N = Natural
- A = Ash
- G = Gold
- C = Copper
- V = Violet
So a 6A is basically a 6.1. A 7GV would be a Level 7 Gold Violet. It’s the same logic, just a different alphabet. Most pros still mentally convert these back to the 1-10 decimal system because it’s the "Latin" of the hair world.
Common Misconceptions That Ruin Dye Jobs
One of the biggest lies in the beauty aisle is that "Light Ash Brown" (usually a 5.1 or 6.1) will make your dark hair lighter and "cool."
If you have dark brown hair (Level 3) and you put a 6.1 on it with a low-volume developer, you will likely see... nothing. Or worse, you’ll see a slightly muddier version of your current color. Dye doesn't lift dye. If your hair is already colored dark, you can't just put a higher number on top and expect it to work. You have to strip the old color first.
Another one? "The color is too dark, so I'll just wash it a lot." While some toners fade, a "Permanent" color at a Level 4 is going to stay a Level 4. The tone (.1 or .3) might wash out, but the level (the 4) is there until it grows out or gets bleached.
Actionable Steps for Your Next Color Session
Don't just wing it. If you're doing this at home or talking to a new stylist, follow these steps to use hairdressing colour chart numbers like a pro:
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1. Identify your natural level. Look at your roots in natural sunlight. Are you a 3 (Dark Brown), a 5 (Medium Brown), or a 7 (Dark Blonde)? Be honest. Most people think they are darker than they actually are.
2. Decide your goal level. Stay within two levels of your natural start if you’re doing it yourself. Going from a 5 to a 9 at home is a recipe for chemical burns and orange hair.
3. Choose your "Reflect" based on your skin tone. If you have cool undertones (blue veins), .1, .2, and .7 usually look best. If you have warm undertones (greenish veins), .3, .4, and .6 will make your skin glow.
4. Check the "Secondary Tone." If you want a copper-gold but don't want to look like a penny, look for something like 7.34 (more gold than copper) rather than 7.43 (more copper than gold).
5. Understand the Developer. The numbers on the tube are only half the story. You need "Developer" (Hydrogen Peroxide) to make the color work. 10 Volume deposits color. 20 Volume lifts one level and covers grey. 30 Volume lifts two to three levels. If you use a Level 8 color with 10 Volume developer on Level 6 hair, it’s not going to do much.
The hairdressing colour chart numbers system is a tool, not a magic wand. It tells you the chemistry of what's in the tube, but it can't account for the history of your hair—the box dye you used three years ago or the chlorine from the pool. If you're ever in doubt, especially when moving more than two levels away from your current shade, go see a professional. Tell them you’re looking for a "Level 7 with a .12 reflect." They’ll be impressed you speak the language, and you’ll be much more likely to walk out looking like yourself—only better.
To get the most out of your color, always perform a strand test on a small, hidden section of hair near the nape of your neck. This shows you exactly how the hairdressing colour chart numbers will react with your specific hair porosity and underlying pigments before you commit to your whole head. Keep a notebook of the numbers you use; hair grows about half an inch a month, and having the exact formula recorded makes root touch-ups infinitely easier and more consistent over time.