Norwood Scale

What the Norwood scale actually measures

The Hamilton-Norwood scale is a classification, not a score. O’Tar Norwood published it in 1975 after examining 1,000 men, revising the eight-type system the anatomist James Hamilton had described in 1951. It sorts male pattern hair loss into seven patterns by what the scalp looks like, and it has stayed the standard for fifty years because the seven patterns are genuinely distinguishable from one another.

Two things move independently, and the scale tracks both. The frontal hairline recedes at the temples, leaving a triangular notch on each side and an island of hair in the middle. Separately, the crown thins from the whorl outwards. Stages I to III are about the hairline alone. Stage IV is the first where both are present, and from there the scale is really counting down the band of hair that still runs across the top between them: moderately dense at IV, narrow and sparse at V, gone at VI, and at VII only a horseshoe of hair left around the sides and back.

Norwood also described patterns that do not fit that progression. Type III vertex is crown-led loss with the hairline no further back than a standard Type III. The four Type A variants — IIA, IIIA, IVA and VA — are the frontal branch: the hairline marches straight back as one front, with no mid-frontal island and no separate bald spot at the crown. Rhodes and colleagues classified 12% of men aged 18 to 49 as having this predominantly frontal pattern, which is a lot of men looking at a standard plate and finding nothing that resembles them.

The Norwood scale, stage by stage

The seven published stages. Read the middle two columns first — the hairline and the crown move independently, and most of the scale is about how much hair is left between them.

Every row, including the band column, is generated from the same stage data the diagram is drawn from, so the table and the picture cannot disagree. Descriptions follow Norwood’s definitions as summarised in Gupta and Mysore (2016).

The variants Norwood described separately

Type III vertex is crown-led loss. The four Type A patterns are the frontal branch — the hairline recedes as one front, with no mid-frontal island and no separate bald spot at the crown.

Norwood noted that hair loss more severe than Type VA cannot be distinguished from Type VI or VII, so the Type A branch stops there.

Frequently asked questions

What Norwood stage is normal for my age?

There is no "normal" stage for an age, but there are figures. In a community study of men aged 18 to 49, Rhodes and colleagues found 42% had Type III or greater — the point Norwood counted as baldness — rising from 16% of men aged 18 to 29 to 53% of men aged 40 to 49. A Norwood II mature hairline in your twenties is extremely common and Norwood did not classify it as baldness at all.

Does the Norwood scale predict how bald I will get?

No. It is a description of a scalp today, not a trajectory. Norwood’s 1975 paper was a cross-sectional survey of 1,000 men — it recorded which of the seven patterns each man showed at the age he was, not what happened to any individual over time. Nothing in the classification tells you whether you will move from Type III to Type IV, or how fast, or whether you will stop.

At what Norwood stage do men usually start treatment?

The licensed labelling is a better guide than a stage number, and it points at the crown. The FDA label for PROPECIA (finasteride 1 mg) states that "Efficacy in bitemporal recession has not been established", and its trials enrolled men aged 18 to 41 with mild to moderate loss. The Drug Facts for 5% minoxidil foam say it is "to regrow hair on the top of the scalp (vertex only)" and that it "is not intended for frontal baldness or receding hairline". So the evidence is strongest for Type III vertex, IV and V, and thinnest for the temple recession of Types II and III.

What is the difference between Norwood 2 and Norwood 3?

Depth. Norwood II is a triangular, usually symmetrical recession at each temple with the mid-frontal hair still well forward — Norwood did not count it as baldness. Norwood III is the same shape gone deeper: the recessions are bare or only sparsely covered, and Norwood treated Type III as the minimum extent of hair loss sufficient to be called baldness. It is the single most consequential step on the scale, because it is where the classification changes its mind about what it is looking at.

What is a Norwood 3 vertex?

Crown-led loss. In Type III vertex the hair loss is primarily at the whorl, with frontotemporal recession present but no deeper than a standard Type III. It is listed separately because the ordinary Type III has no crown involvement at all, and because the vertex is the one area both licensed medicines were actually studied in — the minoxidil 5% foam label names the vertex explicitly.

What are the Norwood A variants?

The frontal branch of the scale, covering roughly 12% of men aged 18 to 49 in the Rhodes study. Norwood defined them by two features: the anterior hairline recedes to the rear as one front without leaving an island of hair in the mid-frontal region, and no separate bald area develops at the crown. There are four — IIA, IIIA, IVA and VA — graded by how far back the front has travelled relative to the ear canal, and loss more severe than VA cannot be told apart from Type VI or VII.

Can I stage myself accurately from a photograph?

Approximately, and only for the frontal half. Matching yourself to a drawing is not the same act as a clinician examining a scalp under light, and two things in particular are hard from a mirror: the crown, which you cannot see without a second mirror or a phone camera, and diffuse thinning, which reduces density without changing the pattern and which the Norwood scale does not capture at all. Use a stage to describe what you are seeing, not to decide what is happening.

Sources

1. [1]Norwood OT. Male pattern baldness: classification and incidence. South Med J. 1975;68(11):1359–1365
2. [2]Hamilton JB. Patterned loss of hair in man; types and incidence. Ann N Y Acad Sci. 1951;53(3):708–728
3. [3]Gupta M, Mysore V. Classifications of Patterned Hair Loss: A Review. J Cutan Aesthet Surg. 2016;9(1):3–12
4. [4]Rhodes T, Girman CJ, Savin RC, et al. Prevalence of male pattern hair loss in 18-49 year old men. Dermatol Surg. 1998;24(12):1330–1332
5. [5]PROPECIA (finasteride) tablets, US prescribing information, Organon LLC — DailyMed
6. [6]Men’s Rogaine (minoxidil 5%) topical aerosol foam, OTC Drug Facts, Kenvue Brands LLC — DailyMed