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The Hair Porosity Test
Nine questions, about three minutes. Answer about how your hair behaves on a normal wash day — water and product on hair that hasn't been recently clarified or heavily oiled. No cup of water needed. You get low, medium, high or mixed, with the answers that produced it, and a two-minute spray check to confirm it.
Your answers stay in your browser — nothing is uploaded, and there's no email or sign-up to see the result.
The short answer
What is hair porosity?
Hair porosity is how easily your hair takes in water and holds on to it, set by how flat or open the cuticle — the outer layer of each strand — lies. Low porosity resists water and product; high takes both in fast and lets them out fast; medium sits between. One head can carry more than one.
The four results
What your result means
Each result describes how your hair behaves on the days you answered about, not what it is for good. Low and high have their own guides; medium and mixed are explained in full here because they don't need one.
Low
The cuticle — the outer layer of each strand — lies flat, so water and product take longer to get in, and what doesn't get in sits on top. That's why the shower takes a while to soak it through, why a leave-in can feel like a film, and why a mask does more under a cap or warm towel: heat lifts the cuticle a little. Once water is in, it stays in, so air-drying is slow. Light products, and applying to damp rather than dry hair, tend to get further than more product.
Low porosity in the guideMedium
Water and product go in at a normal pace and stay put — most products behave the way the label describes. Medium isn't a hedge; it's where most hair sits, which is why it doesn't get its own page here. What usually changes the picture is buildup, a color or bleach, or ends that have aged past the roots — the reasons porosity shifts over time.
High
The cuticle is open or roughened, so water and product go in fast — and out fast. That's why hair can soak in seconds, drink up a cream and still feel dry by evening, and why it air-dries quickly. It's common after bleaching, heat styling or chemical treatments, and it also occurs in hair that has never been treated. Richer products and something to seal them in tend to last longer on hair that behaves this way.
High porosity in the guideMixed
Different parts take water and product at different speeds — most often the ends faster than the roots, sometimes the front faster than the back. Ends are older and have been through more washing, sun and styling than new growth, so a gap between them is the normal direction of travel. In practice it means one routine rarely fits the whole head: the more porous part wants what high porosity hair wants, the less porous part wants the opposite, and the result reads them as a pair instead of averaging them away.
If you did the float test
Why the float test tells you less than it seems to
If you're here because a strand did something in a glass and you're none the wiser, you're in good company. The most common report isn't "it sank" or "it floated" — it's this:
"My hair floats but everything else about it says high porosity."
"It has characteristics of both, so who knows."
"Half floated, half sank — now I'm more confused than before."
Surface tension holds it up
A clean, dry strand rests on the surface of water whatever its porosity — the water has to break through the surface before the strand can take any in. Given time and enough dunking, all hair will sink, which is why instructions disagree on how long to leave it and why the result depends more on the clock than on your hair.
Residue changes the answer
Oil, conditioner, gel and hard-water film all change whether a strand takes in water. A coated strand floats however open its cuticle is; a freshly clarified one may not. So the test often reads what's on the hair, not the hair.
One single strand doesn't speak for the head
Porosity varies along one strand — the ends are older and more porous than the root end — and across your head, front to back. One shed strand in one glass is one data point about one part, which is why "characteristics of both" is such a common outcome.
Every porosity tool that ranks well for this search is a behavior questionnaire, not a strand in water — the float test is listed first in most articles and used by none of the tools. The questions above ask about the same things the float test was meant to stand in for, on your whole head, over a normal week.
How to double-check
The spray check, and a second opinion
The test doesn't depend on any experiment. But if your result came back close or conflicted, one two-minute check settles most of it: the spray check is the third question done for real, and you come back and change that answer.
The spray check
- Take a small dry section that hasn't had product since it was washed.
- Mist it with plain water from about 20 cm away — two or three sprays.
- Watch it for a count of ten.
- Read it: soaks straight in and darkens → behaves like high porosity; sits a moment then sinks in → medium; beads up or rolls off → low. Then come back and change your answer to the spray question.
Then come back and change your answer to the spray question. That's the whole loop — the check doesn't produce a separate result.
The slide check — as a second opinion only
Slide a strand between two fingers from the end toward the root. Bumpy or catching means a more open cuticle (higher); smooth means more closed (lower). It's easy to misread on colored or very fine hair, so use it only to confirm the spray check, never on its own.
Signs at a glance
Signs of low and high porosity
Behaves like low porosity
- Takes a while to get wet through in the shower — water runs off at first
- Air-dries slowly, half a day or more
- Sprayed water beads up or rolls off
- Leave-ins and creams sit on top, feel like a film, or flake
- Deep conditioner does more under heat
Behaves like high porosity
- Soaked through within seconds
- Air-dries fast, often within the hour
- Sprayed water soaks straight in and darkens the strand
- Drinks up product and still feels dry by evening
- Common after bleach, heat or chemical treatments — but not only then
Most of the low-porosity signs are also signs of product buildup. If the strand feels coated between washes, clarify once before you trust the reading.
Better or worse
Is it better to have high or low porosity?
Neither. Porosity isn't a grade — it describes how your hair handles water, and each way of handling it has products that work with it and products that work against it. Low porosity hair keeps moisture once it's in and takes longer to get it there; high porosity hair takes it in fast and loses it fast. The useful question isn't which is better but which one yours behaves like, so the routine matches. There's no porosity to aim for, and none that needs changing.
Nine questions, three minutes, no glass
Answer about how your hair behaves on a normal wash day and you get low, medium, high or mixed, with the answers behind it and a two-minute check to confirm it.
Add your curl pattern, thickness and density
The hair type quiz takes about four minutes and reads the other three axes.
Curl pattern, thickness and density each get a section in the hair types guide.
Sources & limitations
Style Look Lab method and limits: a band describes how the cuticle is behaving right now — how quickly hair takes water in and how quickly it lets it go — not the condition of the hair, and nothing here is a diagnosis. The judging runs on that behavior rather than on the float test: a clean, dry strand rests on the surface whatever its porosity, product residue changes what it does, and one shed strand does not stand for a whole head. Which answer moves which band, how contradictory answers are settled, and the confidence wording are internal — no validated questionnaire-to-band reference data exists behind them, and nobody outside this site has checked them. Styling state, bleaching or heat, and how long the hair is all change the reading, and the same head can read one way at the roots and another at the ends. The curl codes on the quiz side of this site come from a chart with disputes of its own; porosity is a separate axis, and a band here says nothing about that code.
- Lab Muffin Beauty Science — Hair porosity tests are a lie — Explains why a strand resting on water is surface tension rather than a porosity reading.
- Science-y Hair Blog — Hair Porosity: The Float Test Part Two — Side-by-side strands with oil, conditioner and gel show residue and time decide the outcome; it does not validate this test.
Asked before you ask
Common questions
Do I need to do the water test?
No. The test asks about things you already know — how long the shower takes to soak your hair, how long it takes to air-dry, where a leave-in goes — and scores those. A strand in water is held up by surface tension and pushed around by residue, so it tells you less than a week of wash days does. If you've already done it and got a confusing answer, that's the usual outcome, not a sign your hair is odd.
How long does the hair porosity test take?
About three minutes for the nine questions, and the result is immediate. The optional spray check takes two more. If you're asking how long to leave a strand in water: instructions disagree, and a strand that hasn't broken the surface can float indefinitely — that disagreement is the reason the float test isn't used here.
Can you change your hair's porosity?
It changes on its own more than most people expect. Bleach, heat and chemical treatments raise it; buildup can make hair behave lower than it is; and the ends are always further along than the new growth at the roots. You can't set it to a number, but a clarifying wash, less heat, or a trim all move how it behaves — which is why a result describes your hair now, not for good.
Can different parts of my hair have different porosity?
Yes, and it's common enough that this test has a result for it. Ends are older than roots and have been through more washing and styling, so they're usually more porous; some people also find the front or edges take water faster than the back. When you say parts behave differently, the result is mixed: an overall reading plus which part is the more porous one, rather than an average that fits neither.
Is frizzy hair high or low porosity?
Either. Frizz is hair reaching for moisture in the air, and hair can do that because the cuticle is open and lets moisture out (behaves high) or because product and water never got in properly in the first place (behaves low). Frizz on its own doesn't settle it; how fast your hair soaks through and air-dries does.
What is mixed porosity?
Mixed porosity means different parts of your hair take water and product at different speeds — most often the ends faster than the roots. This test reads it as an overall band plus a direction ("ends more than roots"), not as a separate band for each part, because the parts are relative to each other rather than set.
Do Asians have low or high porosity hair?
Porosity describes the state of the cuticle, not where someone's family is from. Any porosity occurs in any ethnicity, and it changes with bleach, heat, buildup and age along the strand, so there's no ethnicity-level answer to give. The same goes for curl pattern: the charts describe curl width and shape, and they say nothing about ancestry.