Hair porosity estimate from a float test result

A hair porosity estimator turns the outcome of a simple water float test into a useful classification. In the float test, a clean strand of hair is placed in a glass of water: if it sinks fast the hair tends to be high porosity, if it sinks slow it is usually normal porosity, and if it floats it is typically low porosity. Enter what your strand did and this tool returns the porosity class, a plain-language summary of what it means for the hair cuticle, and a list of general care implications such as sealing moisture, using protein, or clarifying buildup.

What the float test measures and how it is read

Hair porosity describes how easily water and products pass through the cuticle, the outermost layer of overlapping cells on each strand. The float test is the most popular at-home way to get a rough read on it: take a clean, product-free strand of shed hair, let it sit a moment so surface tension settles, and drop it into a glass of room-temperature water. Watch what happens over a couple of minutes.

A strand that sinks fast to the bottom absorbed water readily, which suggests raised or damaged cuticles and therefore high porosity. A strand that sinks slow, drifting down gradually or hovering mid-glass, suggests a balanced cuticle and normal porosity. A strand that floats at the surface repelled the water, which points to flat, tightly closed cuticles and low porosity.

The test is a heuristic, not a lab measurement: oils, conditioners, or hard-water residue on the strand can skew the result, which is why the strand should be freshly washed and fully dried first. This capability takes the observed outcome of that test, normalizes the wording, and maps it to the standard three-class interpretation used in hair care guidance.

Using the classification in a care routine

The classification matters because the three porosity classes respond differently to the same products. High porosity hair takes moisture in quickly but loses it just as fast, so the practical advice centers on layering moisture and then sealing it with oils or butters, using periodic protein treatments to help patch gaps in the cuticle, favoring leave-in conditioners, limiting heat and chemical processing, and rinsing cool to help the cuticle lie flatter.

Normal porosity hair is the balanced case: regular conditioning with occasional deep treatments, tolerance for both lightweight and richer products, and protection from cumulative damage to keep it that way. Low porosity hair resists absorption, so products should go onto damp, warm hair, lightweight water-based formulas beat heavy butters that sit on the surface, gentle heat during deep conditioning helps open the cuticle, and occasional clarifying removes the buildup that accumulates because little is absorbed.

Treat the result as a starting hypothesis: porosity can vary along one head of hair and changes with damage over time, so re-testing periodically and combining this signal with how the hair actually behaves under products gives the most reliable routine.