Free test · 3 questions + float test · no signup
Hair Porosity Test: Is My Hair Low, Medium or High Porosity?
A guided float test with a 4-minute timer, and three questions you answer while the strand sits in the water, tell whether your hair is low, medium or high porosity, with a routine for yours. The float test counts least, because it is the least reliable part, and you can skip it.
CostFree
TimeAbout 4 min
SignupNone
DataKept on device
01 / 05
Start the float test, or skip it
Take one clean, dry strand from your brush, washed with no product since. Drop it into a glass of room-temperature water and start the timer, then answer the next three questions while it sits.
The science
What is hair porosity?
01
Hair porosity is how readily your hair takes up water, and how fast it loses it again. It is set mostly by the cuticle, the overlapping scales on the outside of each strand: when they lie flat, water and product are slow to get in (low porosity); when they are raised or worn away, hair soaks water up fast and lets it go fast (high porosity). Damage raises it. Labs measure porosity with gas sorption, and in one such study oxidative bleaching nearly tripled hair’s surface area within the first minute (Hessefort and colleagues, Journal of Cosmetic Science, 2008).
02
This hair porosity test reads it from what you can observe. Your chemical and heat history counts most, 3 points for bleaching, perms or relaxers and 2 for daily heat, because it is the one answer tied to measured damage. How long your hair takes to air-dry and how it takes water and product count 2 each. The float test counts 1. The most points wins; a tie that includes medium, or between low and high, reads medium, and a lead of 2 points or more is called clear.
03
Low, medium and high are hair care categories, not lab ones: no study sets cut-offs for them, so neither does this test. Porosity also changes along a strand, and bleached ends often read high while the roots read low or medium, so treat your result as a guide to the products and habits that fit most of your hair.
How to do the hair porosity float test
The float test takes 4 minutes, and this test runs its timer while you answer the questions, so it adds no waiting. Set it up so oil and product do not decide the result for you.
- Step 1Wash your hair with shampoo and skip conditioner, leave-ins and oils, then let it dry fully.
- Step 2Take a shed strand from your brush or comb; a clean, dry one gives the fairest read.
- Step 3Fill a clear glass with water at room temperature and drop the strand onto the surface.
- Step 4Start the 4-minute timer here and answer the three questions while it sits.
- Step 5When the timer ends, look at the glass from the side: still floating on top, hanging in the middle, or sunk to the bottom.
A strand still on top reads low, one in the middle medium, one on the bottom high. Whatever it does, it counts for less than any of the three questions.
Is the float test accurate?
We looked for evidence and found none either way: no published study tests the float test against a lab measure of porosity, and Healthline’s guide, reviewed by the dermatologist Raechele Cochran Gathers, says it is not scientifically validated. What we can say is why it is easily fooled.
Dry hair is denser than water, about 1.32 grams per cubic centimeter (Wu, Journal of the Society of Cosmetic Chemists, 1982), so any strand sinks once water has wet it through. Until then it floats on surface tension, and how long that lasts depends on the oil from your scalp, conditioner or product left on it, and how thick the strand is, as much as on its cuticle. A strand of high porosity hair with a little oil on it can float; a clean strand of low porosity hair can sink.
The signs that hold up better are the ones you live with: how long your hair takes to dry, whether water beads or soaks in, how products behave, and whether it has been bleached, permed, relaxed or heat-styled daily. Those are the three questions, and they carry most of the result.
Low, medium and high porosity hair compared
What each porosity looks like day to day. The test’s questions read the first three rows.
| Sign | Low | Medium | High |
|---|---|---|---|
| Air-drying | Slow, stays damp for hours | As you would expect for its length | Fast |
| Water and product | Water beads, products sit on top and build up | Wets through, products sink in | Soaks everything up, dry again soon |
| Usual history | Never bleached or chemically treated | Some color or heat | Bleach, perms, relaxers or daily heat |
| Float test | Floats on top | Hangs in the middle | Sinks |
Low porosity hair test: signs and routine
Low porosity hair has a tight, flat cuticle. Water and product are slow to get in, so it takes long to wet and long to dry, and creams sit on top. Once moisture is in, it stays. Its usual problem is buildup, not dryness.
- Step 1Wash: A clarifying shampoo every few washes clears the buildup that low porosity hair collects.
- Step 2Condition: On soaking wet hair, and give it time: a shower cap or warm towel over a deep conditioner is the usual low porosity practice.
- Step 3Products: Light, water-based leave-ins and lotions. Heavy butters and thick oils sit on top and weigh it down, so use them sparingly.
- Step 4Heat: Low or medium heat with a heat protectant, like every porosity.
Medium porosity hair
Medium porosity hair takes up water and product at an even pace and holds it, which makes it the easiest to care for. The job is to keep it there, because bleach and daily high heat are what move hair to high porosity.
- Step 1Wash: As your scalp needs it, shampoo on the scalp rather than the lengths.
- Step 2Condition: Every wash, with a deep conditioner every week or two.
- Step 3Protect: A heat protectant and low or medium heat; bleach is what moves hair to high porosity.
High porosity hair: signs and routine
High porosity hair has a raised or worn cuticle, most often from bleach, chemical treatments or heat. It soaks water and product up fast and loses them fast, so it dries quickly, frizzes and tangles. Coconut oil is the one oil with evidence here: of mineral, sunflower and coconut oil, only coconut oil cut the protein lost from damaged and undamaged hair when used before and after washing (Rele and Mohile, Journal of Cosmetic Science, 2003). The heat advice is the American Academy of Dermatology’s.
- Step 1First: Cut back on what raised it: bleaching and daily high heat. Bleach nearly tripled hair’s measured surface area within a minute in lab tests.
- Step 2Pre-wash: Coconut oil before washing: of three oils tested, it was the only one that cut protein loss from damaged hair.
- Step 3Condition: The full length every wash, with a protein or bond-repair treatment every few weeks.
- Step 4Seal: A leave-in, then a cream, then a little oil on the ends, to slow how fast it dries out.
- Step 5Heat: A heat protectant first, and low or medium settings; trim the split ends.
Hair porosity quiz and your hair type
Porosity and curl pattern vary separately: two people with the same curl type can need opposite products. The hair type quiz finds your type from 1A to 4C with a care routine for it, and the two results together pick your products. If you are thinking about lightening your hair, the hair color matcher for your skin tone shows the shades that suit you; the lighter a shade is than your natural color, the more bleach it takes and the higher your porosity will go.
FAQ
Common questions
What is my hair porosity?+
If your hair takes hours to dry, water beads on it and products sit on top, it is likely low porosity. If it dries quickly, soaks up product and feels dry and frizzy again soon, especially after bleach or daily heat, it is likely high. In between is medium. This test weighs those signs and an optional float test, and gives the routine for yours.
How do I know if my hair is low porosity?+
Low porosity hair is slow to get wet and slow to dry, water beads on it in the shower, and creams and oils sit on top or build up instead of sinking in. It is usually hair that has never been bleached or chemically treated. A strand that stays floating in the float test points the same way, but it is the weakest of these signs.
Does the hair porosity float test work?+
Not reliably. We found no study that tests it against a lab measure, and a dermatologist-reviewed guide calls it not scientifically validated. Hair is denser than water, about 1.32 grams per cubic centimeter dry, so every strand sinks once it is wet through; how long it floats first depends on surface tension and on oil, conditioner or product left on the strand as much as on porosity. That is why it counts for 1 point here and can be skipped.
How long do you leave hair in water for the porosity test?+
There is no standard time, and home guides vary. This test gives the strand 4 minutes and asks you three questions while it sits, then asks where the strand is: still on top, hanging in the middle, or sunk to the bottom.
Can you change your hair porosity?+
Not on hair that has already grown. Damage that raised porosity does not undo itself: conditioners, oils and bond treatments coat or fill the strand and slow water loss, and new growth comes in at your natural porosity. Trimming off bleached or heat-damaged ends is what removes high porosity lengths. You can stop raising it by cutting back bleach and daily high heat.
Is high porosity hair damaged?+
Usually, yes. Bleach and chemical treatments raise porosity by lifting and wearing away the cuticle, and heat and long sun exposure wear it too. The care is the same whatever the cause: gentler habits, conditioner on the full length every wash, and products that seal moisture in.
What is the difference between hair porosity and hair type?+
Hair type is the shape of the strand, from straight 1A to coily 4C. Porosity is how the strand takes up water and product. They vary separately, so two people with the same curl type can need opposite products, which is why both tests are worth taking.
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