Many people describe their hair as thick without knowing whether the strands are truly thick or simply abundant.
The words thick and dense often get mixed up, creating confusion when choosing products or explaining needs to a stylist. This guide clears up that confusion with clear, practical checks you can do at home.
You’ll learn how to tell if each strand is genuinely thick and how many strands you have overall. These simple steps help you choose the right cuts, care routines, and styling methods so your hair looks and feels its best.
What do “Thick” and “Dense” Mean in Hair Terms?
- Thickness (or coarse, heavy strands): This describes how wide or full each individual hair strand is. If you can feel a strand’s presence, see its width clearly, or use comparisons like a thread, that’s hair that skews toward “thick.”
- Density: This is about how many hair strands grow on your scalp, i.e. how closely packed your hairs are. Even very fine hair can be dense; very thick hair can be sparse. Olaplex emphasizes that thick vs dense aren’t synonyms.
If you only test density (scalp visibility, fullness), you might think you have “thick” hair when in fact your strands are fine. That leads to mismatched treatments, like using heavy creams or thickening shampoos unnecessarily, or cutting mistakes. So, test both.
How to test strand thickness
1. The Single-Strand Pinch Test
Pull a single hair from your head (ideally from a less visible spot). Pinch it lightly between two fingertips (thumb and forefinger) and feel it.
- If you barely sense it or it feels almost wispy, that’s more like a fine strand.
- If you clearly feel the strand’s girth or grain, you’re likely working with a thicker strand.
Redken recommends this as a fundamental test. Their experts often use this tactile sense to categorize hair types.
2. Thread or Sewing-Thread Comparison
Take one hair strand and place it next to a sewing thread (of a standard thickness).
- If the hair is similar or thicker to the thread under normal lighting, it leans “thick.”
- If it appears much thinner, it’s probably fine.
Prose and other brands use this as a simple visual benchmark. You don’t need lab instruments to get a ballpark idea.
3. Visibility Against a Light Background
Hold a hair strand between your fingers and place it against a white or light-colored background (paper, wall, or sheet).
- If the strand is nearly invisible or looks like a faint line, it’s fine.
- If it shows as a strong line (dark, noticeable width), that suggests thickness.
This test relies partly on your eye, but when paired with the tactile test, it gives a clearer picture.
4. Known Numeric Benchmarks (for Comparison)
Some beauty editors and trichologists reference ranges:
- Fine hair might be ~50 microns in diameter
- Coarse or “thick” strands might be ~120 microns or more
You won’t measure this directly, but knowing the scale helps you understand that “fine” vs “coarse” isn’t just aesthetics. (Byrdie touches on these ranges.)
5. Rollability / “Roll Test” (Less Precise)
Some guides (like Secrets de Loly) suggest rolling a strand between two fingers.
Fine strands tend to roll easily or slip; thicker ones resist bending or feel stiffer. But this is less reliable if the hair is chemically treated or dry.
How to Test Density (often Confused as Thickness)
1. Ponytail Circumference Method
Tie your hair in a tightly pulled ponytail (dry, unstyled) and measure the band’s circumference (i.e., how thick the ponytail “rope” is).
- Under ~2 inches (~5 cm): low density
- Around 2–3 inches (5–7.5 cm): medium density
- Over 3–4+ inches (7.5+ cm): high density
This isn’t perfect (hair length, layering, and curls affect it), but many pros (including guides by Living Proof) use it as a rough indicator of density.
2. Scalp-visibility test
Stand in bright light with your hair natural (no heavy products) and look straight down at your part or throughout your scalp.
- If you still see distinct scalp between hairs, you likely have lower density.
- If your scalp is mostly hidden by hair, you likely have high density.
This is one of the most commonly cited methods to measure the density.
3. Volume vs flatness in unstyled state
When your hair is clean, air-dried, and without product, does it lie flat and you can see scalp, or does it puff out and look full?
- If hair overall seems “flat” and skin shows underneath, density is likely low.
- If hair seems to hold body and fullness even without styling aids, density is higher.
But be careful: wave, curl, or texture can mislead here.
How to integrate both tests and interpret results
By now, you should have a sense of thickness (strand width) and density (hair count). Use these combined profiles to understand your hair better. Below are possible combinations and what they feel like:
| Strand Type | Density | What you’ll see/feel | Common challenge or trait |
|---|---|---|---|
| Fine strand + high density | Your ponytail is full and scalp hard to see; individual strands feel delicate | Looks voluminous but fragile | Hair may lack strength; breakage risk; product weigh-down |
| Fine + low density | Hair looks sparse, scalp visible; strands feel very soft or thin | May look thin overall | Need lightweight volume without heaviness |
| Thick strand + high density | Hair looks full, feels “substantial” | Volume plus weight | Might be heavy and resist styling |
| Thick + low density | Hair feels coarse or sturdy, but scalp shows through | Strands impressive, overall volume moderate | Need strategies to boost fullness without overburdening it |
If your strands resist multiple tests for thickness, and your density checks show scalp is well-covered or ponytail is robust, you truly have thick hair (both in strand and number).
Why Knowing True Thickness Matters
- Product choice
Heavy creams, waxes, butters may weigh fine hair down; they may be suitable for thick strands. If you misdiagnose, your products may under- or over-perform. - Cut and layering
A stylist who thinks you have thick hair might chop too much off fine-dense hair, leaving it limp or lifeless. Conversely, fine-data styling might undercut the shaping for truly thick hair. - Styling technique
Blowouts, curlers, straighteners—each behaves differently on different thicknesses. What works on coarse hair might fry fine hair; what works volumizing fine hair might not move thick hair well. - Health & treatment strategies
Thicker strands may tolerate certain treatments (deep conditioners, oils) better. Fine strands may break more easily or need protein/strength support. - Expectations management
If you know your hair is fine but dense, you won’t be disappointed when “thick cream” weighs it down. You’ll gravitate toward lighter formulas that enhance lift etc.
Wrapping Up
Understanding the difference between strand thickness and hair density helps you care for your hair with confidence.
By combining simple at-home tests, pinch, thread, visibility, ponytail, and scalp checks, you can see whether your strands are truly thick, simply numerous, or somewhere in between.
This clarity guides every choice, from daily products to salon cuts and long-term treatments.
Instead of guessing, you’ll know exactly what your hair needs to stay healthy, manageable, and styled the way you like.