The Norwood Scale, Stage by Stage

The Hamilton-Norwood scale is the map clinicians use to describe where male pattern hair loss has reached. It has seven types and a set of variants, it was set out in its modern form by Norwood in 1975, and it describes shape rather than speed — which is the single most misread thing about it.

A 2016 review of patterned-hair-loss classifications in the Journal of Cutaneous and Aesthetic Surgery goes through the types as originally described, and that description is what this page follows.

The seven types

1. Type I. There is minimal or no recession of the hairline. This is the baseline, not a stage of loss.
2. Type II. Triangular, usually symmetrical areas of recession at the frontotemporal hairline — the front corners moving back. This is the point at which most men first notice anything.
3. Type III. The review describes this as the minimal extent of hair loss sufficient to be considered baldness. There is also a type III vertex variant, where the crown is the area losing hair while the front corners have receded only a little.
4. Type IV. Loss is more extensive than type III, with a band of moderately dense hair still crossing the top of the head and separating the front from the crown.
5. Type V. The vertex and frontotemporal areas are still separated, but by a narrower and sparser band.
6. Type VI. The bridge of hair that crosses the crown is gone, with only sparse hair remaining across it.
7. Type VII. The most severe form, leaving a narrow horseshoe of hair around the sides and back of the head.

The A variants

Types IIA, IIIA, IVA and VA describe a different route to the same place. The review identifies them by two features: the anterior hairline recedes without leaving an island of hair in the mid-frontal area, and the crown does not bald separately at the same time. In plain terms, the whole front hairline walks backwards as a line rather than the corners and the crown meeting in the middle.

The A variants are less common than the main series, and they matter for one practical reason: a man following an A pattern can look less bald from above than someone at the equivalent main-series type while having lost as much hair overall.

What the scale does not tell you

It says nothing about speed. There is no interval attached to any type, and no rule that a given type leads to the next. Two men at type III can be at the same type in ten years and at type VI respectively, and nothing in the classification distinguishes them in advance.

It says nothing about cause. It was drawn for male pattern hair loss. Put a different kind of hair loss on it and you get a number describing a shape that is being produced by something the scale was never about. Diffuse thinning all over the scalp, round patches, and a scalp that looks inflamed or scarred are all outside it — the signs that it is not pattern baldness is the page for that.

It says nothing about what to do. A type is a description, not an indication. What the evidence supports, and how strong that evidence is, is the job of the index of hair-loss treatments, and what is appropriate for one person is a decision for a doctor.

Why clinicians still use it

Because it is a shared vocabulary. A scale everyone knows lets a dermatologist record a pattern in one character, compare it with the same patient's pattern two years later, and let researchers sort trial participants into groups that can be compared. Several of the randomised trials pooled in the hair-loss literature enrolled by classification, which is one reason trial results often apply to a narrower band of men than the marketing built on them suggests.

It is a blunt instrument all the same. Hair density varies enormously inside a single type, and photographs of the scale circulate online in versions that are redrawn, relabelled and sometimes simply wrong. If where you sit on it matters to a decision, the person who should place you on it is the person who can look at your scalp.

Where the scale came from

The classification carries two names because it had two authors. Hamilton set the benchmark for describing male patterned hair loss, laying out the evolutionary stages and building a classification on them; Norwood later added patterns Hamilton's version had not described, and published the seven-type form in the Southern Medical Journal in 1975. That is the version in clinical use today, and the reason every chart you see online has the same seven columns.

Other classifications exist, and the 2016 review that this page follows compares a number of them. None has displaced Hamilton-Norwood for men, largely because a scale is only useful if everyone already knows it.

If you think you are between two types

You probably are, and that is normal. The types are points on a continuum drawn to be recognisable, not boxes with hard edges, and a real scalp rarely matches an illustration exactly. Crown density in particular varies enormously inside a single type, and lighting, hair length and how wet the hair is change what a photograph shows far more than most people expect.

Two practical consequences follow. Comparing your own photographs is more informative than comparing yourself with a chart, as long as the photographs are taken in the same place, in the same light, with hair the same length. And a type recorded by a clinician who examined your scalp is worth more than a type you assigned yourself from a diagram, because the thing they are checking is not only the shape but whether the shape is being produced by what the scale assumes.

What the pattern is telling you

The distribution itself is the useful signal. Loss concentrated at the temples and crown, developing over years, in a man, in a family where it is common, is the pattern this scale exists to describe — and the pattern the approved treatments were tested against. Loss that ignores that distribution is a reason to ask a different question, starting with where the genetics actually come from and ending, usually, in an appointment.