Guides · Norwood scale

The Norwood scale,
in seven stages.

The Hamilton–Norwood scale stages male pattern hair loss in seven steps, from no recession to a narrow horseshoe of hair at the sides and back. It was published in 1975 from a series of 1,000 men, which is also where the often-quoted incidence figure of roughly 35% at age 50 comes from. Where you fall on it is one input (alongside donor density, which matters more) into how many grafts a transplant can realistically use.

How many grafts I need
The seven stages

Viewed from above. Front of the head at the top.

Our own schematic of a published classification: drawn, not photographed, because this site publishes no patient imagery.

  1. I No recession
  2. II Temples
  3. III Deep temples
  4. III vertex Crown opens
  5. IV Bridge holds
  6. V Bridge narrows
  7. VI Bridge gone
  8. VII Horseshoe

Two things the drawing is meant to show that a list of stage numbers hides. First, the temples and the crown recede as separate processes: a man can hold a stage III hairline for years while the vertex opens independently behind it, which is why stage III has a named vertex variant at all. Second, the jump that matters clinically is V to VI, the moment the bridge of hair between front and crown disappears and two manageable areas become one large one. Norwood's 1975 revision also added Type A variants, for men whose hairline retreats straight back without a distinct crown spot ever forming; they are not drawn here.

What the stage does not tell you

What the scale covers, and what it does not.

Clinics quote graft counts per Norwood stage, and it reads as precision. It is not. The scale measures the area you have lost; what can be done about it is set by the area you have kept: donor density, safe donor boundaries, and how much can be harvested without thinning the back of your head visibly. Two men at the same stage VI with different donor densities have materially different options, and the published donor figures on the donor capacity page vary far more between individuals than the stage does.

There is also a timing point the scale makes badly. It is a snapshot, not a forecast: nothing in a stage tells you how fast you are moving through it, and a plan drawn for a stage III man who is heading for stage VI has to reserve donor supply for loss that has not happened yet. That reservation is the single most common thing missing from a cheap plan, and it costs nothing to ask about.

Classification, Type A variants and incidence: Norwood OT. Male pattern baldness: classification and incidence. Southern Medical Journal. 1975;68(11):1359–65, PMID 1188424 (a series of 1,000 adult men) (https://pubmed.ncbi.nlm.nih.gov/1188424/), measured 2026-07-28. The classification originates with Hamilton (1951); Norwood revised it and added the Type A variants. The stage diagram above is our own schematic drawing of that published classification, not a reproduction of any plate from it.

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