Curly hair sits on a spectrum, and the curl type chart — running from 2A loose waves to 4C tight coils — describes where on that spectrum your hair lives. Coil diameter, shrinkage, and density tell you what your hair will actually do in the shower; the letter is the shorthand. This guide covers the full nine-pattern chart, how to test for your type at home, and the one mistake that puts most readers in the wrong category.
How the Curl Type Chart Actually Works
Most curl guides treat the 2A-to-4C chart like it fell from the sky. It didn't. Two distinct systems sit underneath what most people call "the curl chart" — one created in 1997 by celebrity stylist Andre Walker, and one published in 2007 by a team of academic biologists working on a global hair-shape study. They mostly agree. Where they disagree is worth knowing.
Andre Walker's original 1A–4C system
The chart you've seen on Pinterest comes from Andre Walker's 1997 book Andre Talks Hair. Walker, then Oprah Winfrey's longtime stylist, organised hair into four numeric types — straight (1), wavy (2), curly (3), coily (4) — and split each curly category into A, B and C sub-letters running from loosest to tightest. Walker defined 3A as "springy coils with a definite S-pattern and a diameter equal to a piece of sidewalk chalk" — the first time anyone had tied a letter to a measurable object you could hold up to your own hair. The system caught on because it gave wavy and curly people language they'd never had.
What it didn't do: explain why the patterns differed. That work came later.
The peer-reviewed alternative — De La Mettrie et al., 2007
In 2007, a research team led by R. De La Mettrie published a peer-reviewed paper in Human Biology (DOI 10.1353/hub.2007.0036) that measured hair across 1,442 subjects from 18 countries and arrived at eight curl categories rather than nine. Their classification uses three measurements — curl diameter, curl index (how tightly coiled), and waves per centimetre — and the result correlates more cleanly with hair-follicle shape than Walker's letters alone do.
You don't need to choose between them. Walker is the shorthand; De La Mettrie is the science. Most product ranges, including ours, are built around Walker's letters because they're what readers ask for, but knowing the academic taxonomy exists is a good defence against the assumption that 4C is one homogeneous thing (it isn't — by the De La Mettrie measure, "4C" splits into at least two distinct shapes).
What the letter measures vs what it doesn't
The letter measures coil diameter and shape. It doesn't measure porosity (how thirsty your hair is), density (how many hairs per cm² grow from your scalp), or width (how thick each individual strand is). Two people can both type as 3B and have completely different product needs because one is fine-strand low-density 3B and the other is coarse-strand high-density 3B. The chart is a starting point. We'll come back to this in the "Beyond the chart" section.
How to Determine Your Curl Type — the at-home test
The single biggest mistake we see in the Zenvy community is people typing themselves while their hair is wet, in a mirror, after applying product. None of those conditions show your actual curl pattern. Run this four-step test instead.
Step 1 — Wash your hair, no product
Shampoo with a clarifying or gently sulfate-free wash. Do not apply leave-in, cream, gel, mousse, or oil. The goal is to see how your hair behaves without anything weighing it down or holding it up.
Step 2 — Let it air-dry, no manipulation
Don't touch it. Don't run fingers through it. Don't plop, don't scrunch, don't diffuse. Just air-dry. This is the single hardest part because curly hair feels wrong when you can't touch it, but every interaction biases the result.
Step 3 — Compare a curl against the diameter chart
Once fully dry, pull one curl gently down to its natural length and look at the coil. Here are the diameter ranges to compare against:
| Type | Coil diameter | Reference object |
|---|---|---|
| 2A | 25–30 mm | a £2 coin diameter |
| 2B | 18–25 mm | a permanent marker barrel |
| 2C | 14–18 mm | a Sharpie barrel |
| 3A | 10–16 mm | a piece of sidewalk chalk |
| 3B | 6–10 mm | a standard pencil |
| 3C | 5–8 mm | a drinking straw |
| 4A | 4–6 mm | a coffee stirrer |
| 4B | sharp Z-bends, no defined coil | — |
| 4C | 3–4 mm | a sewing-needle eye |
These ranges are what most editorial guides leave out. We've kept the reference objects as well because not everyone owns a ruler, but if you have one, use it.
Step 4 — Take a photo and run it through the Zenvy AI Curl Identifier
If you'd rather skip the ruler, take a clear photo of your dry hair against a plain background and upload it to the Zenvy AI Curl Identifier. The tool maps your photo to one of the nine patterns automatically and flags porosity likelihood at the same time. It's the only live curl-typing tool that any of the major guides offer (we checked) and we built it because every single one of us in the Zenvy team typed ourselves incorrectly the first time.
Type 2 — Wavy Hair (2A, 2B, 2C)
Type 2 is wavy. The strand bends but doesn't loop. From a follicle-shape perspective, type 2 follicles are slightly oval rather than round, which produces an S-wave instead of a true coil.
2A is the loosest pattern: 25–30 mm waves that often look almost straight when dry. Shrinkage is minimal — usually under 15%. The thing 2A wearers usually want is more definition, and the lightweight-product discipline that gets you there is the opposite of what bottle marketing for "curly hair" tells you to do. Read more about 2A hair routine and products.
2B sits in the middle: 18–25 mm S-waves that begin from mid-lengths down, with a flatter crown. Density tends to be medium, and the biggest 2B problem is canopy frizz — the top layer of hair frizzing while the underneath stays in pattern. The fix is layering technique, not heavier product. Our 2B hair guide covers it.
2C is at the boundary between wavy and curly. Coils tighten to 14–18 mm and shrinkage climbs to 20–25%. 2C wearers often try treating their hair as type 3 and end up with weighed-down curls, or treat it as type 2 and end up with no definition. The midpoint products and techniques are real — see the 2C hair guide.
Type 3 — Curly Hair (3A, 3B, 3C)
Type 3 is curly. The strand loops cleanly. Follicles are more elliptical than type 2.
3A is loose ringlets: 10–16 mm coils, the diameter of a piece of sidewalk chalk (Walker's original definition). Shrinkage is 20–35%, density is typically medium, and the standout problem is volume loss — 3A loses its bounce by midday more reliably than any other type. The fix is a medium-hold gel as the final layer. Our 3A care guide goes deeper.
3B is the springy-ringlet pattern: 6–10 mm coils, the diameter of a standard pencil. Density tends to be high (240–300 hairs per cm²), shrinkage climbs to 35–50%, and 3B holds definition naturally if you can stop yourself from touching it while it dries. We wrote a full owner's manual for 3B curly hair.
3C is tight corkscrew curls: 5–8 mm coils, the diameter of a drinking straw, with shrinkage of 45–60%. Density is typically high. 3C sits closest to the border with type 4 and many people genuinely have both 3C and 4A patterns on the same head. See the 3C care guide.
Type 4 — Coily / Kinky Hair (4A, 4B, 4C)
Type 4 is coily. The strand wraps so tightly that shrinkage hides up to 75% of the hair's true length. Follicles are flattened in cross-section, which is what produces the tight coiling.
4A is the loosest type 4: 4–6 mm coils with a visible springy spiral. The pattern resembles type 3 in shape but the strand circumference is type 4. Most major curl guides default to 4A as their "type 4 example," which is why so much advice misses 4B and 4C wearers entirely.
4B doesn't form coils at all. It bends in sharp Z-pattern angles, with little visible curl shape on the head when dry. 4B is the most frequently mis-typed pattern — wearers are often told they have 4C when they don't.
4C is the tightest: 3–4 mm coils packed so densely that the hair reads as a single cottony mass when dry. Shrinkage runs 65–75%, density is typically high, and 4C needs more moisture more often than any other pattern. We've published a foundational guide to type 4 coily hair care that keeps 4A, 4B and 4C distinct rather than lumped together.
Can You Have Two Curl Types at Once?
Yes — and it's common. Most people have at least two patterns side by side: the crown often curls tighter than the nape, the front hairline frequently sits one letter looser than the rest. Type your hair as the dominant pattern (whichever covers the most surface area) and treat the looser sections with slightly less product weight. The Zenvy AI Curl Identifier shows the dominant and secondary pattern for this reason.
The pattern variation isn't random. Hormonal changes — pregnancy, perimenopause, hormonal contraception — can shift one part of your head a full letter looser or tighter. Heat damage shifts pattern in the other direction (away from coiled, toward straight) and doesn't return. Knowing what your "default" pattern is matters for the same reason knowing your resting heart rate matters: it's the baseline you compare today against.
Why the Curl Type Chart Isn't the Whole Picture
The chart tells you about coil shape. It doesn't tell you about three other measurements that matter just as much:
Porosity — how readily your hair absorbs and releases water and product. Low porosity hair (closed cuticle) repels water; high porosity hair (raised cuticle) absorbs everything but loses it equally fast. We've covered the home porosity test in the low porosity curly hair routine. The same coil diameter on a low-porosity head needs heavier products than on a high-porosity head; this is why two friends who both type as 3B can have completely opposite product preferences.
Density — how many hairs grow per cm² of scalp. Low density (under 200/cm²) means scalp is visible when the hair is parted; high density (over 280/cm²) means scalp is hidden. Density determines how much product you actually need — high-density 3B uses three to four times the product of low-density 3B for the same effect.
Strand width — the diameter of a single hair strand, from fine (40–60 μm) to coarse (90 μm+). Width determines how much weight your hair tolerates. Fine 3A and fine 3B both reject heavy creams that work perfectly on coarse 3A. We've published a dedicated best products for fine curly hair guide because the curl-chart-alone advice fails this group reliably.
If we had to summarise the framework in one sentence: the letter tells you the shape, porosity tells you the chemistry, density tells you the quantity, and strand width tells you the weight class.
What to Do Once You Know Your Type
Once you have your letter (or two), the immediate next step is building a routine that fits it. We've published the four-step curly hair routine for beginners as the foundational source for that — it covers cleanse, condition, style-on-wet, and dry, with frequency recommendations by type. Most readers get the most lift from that one article alone.
If you'd rather start with product selection, the how to choose curly hair products by type and porosity guide maps each pattern to the product weights and ingredients that suit it. And if you already know your type and just want a starting kit, the Zenvy curly hair collection is sorted by pattern letter — you can filter to your type and porosity in two clicks.
The single best piece of advice we can give: pick one routine, run it for three weeks, then judge it. Switching products every wash day is the most common reason people think their curls are "broken" when actually the previous product just hasn't fully washed out.
Curl Type FAQ
What are 2A, 2B, 2C, 3A, 3B curls?
Curls are classified on a 9-step chart from 2A to 4C. Type 2 is wavy (2A loose, 2C nearly curly); type 3 is curly (3A loose ringlets, 3C tight corkscrews); type 4 is coily (4A coiled, 4B Z-shaped, 4C tightly packed). The number describes the shape; the letter describes how tight the coil is within that shape. Andre Walker introduced the system in 1997; it's the lens almost every curly hair product range is designed around.
How do I determine my hair curl type?
Wash your hair without product, air-dry it without touching it, then compare one curl against a millimetre-marked ruler. Coils under 5 mm wide are type 4; 5–10 mm coils are type 3; 10 mm+ are type 2. The shape matters too: S-curves are type 2 or 3, Z-zigzags are type 4. For a faster answer, the Zenvy AI Curl Identifier maps a photo of dry hair to one of nine patterns automatically.
Can my hair have two curl types?
Yes — and it's common. Most people have at least two patterns side by side: the crown often curls tighter than the nape, the front hairline frequently sits one letter looser than the rest. Type your hair as the dominant pattern (whichever covers the most surface area) and treat the looser sections with slightly less product weight. The Zenvy AI Curl Identifier shows the dominant and secondary pattern for this reason.
Which curl pattern is rarest?
True 1A (poker-straight) and true 4C are the least common globally, according to the De La Mettrie 2007 distribution. The most common curl pattern worldwide is type 2 (wavy), accounting for roughly 30–40% of the population depending on region. Mid-3 (3B) is the most common pattern in the people who specifically self-identify as curly.
Is the curl type chart accurate for everyone?
It's a useful approximation, not a precise diagnostic. The chart works well for type 2 and type 3 hair because the visible coil shape lines up cleanly with the letter. It's less accurate for type 4 hair, where the De La Mettrie classification reveals shape differences the Walker letters don't capture. Always combine the letter with porosity, density and strand width before choosing products.
