How the Norwood scale works
The Norwood scale describes male pattern baldness in seven stages, from a slightly receding hairline at stage 2 to a horseshoe of hair at stage 7. It is the standard surgeons use to plan and compare cases.
Each stage has a typical surface area to cover, which translates into a graft range. Density is the other half: around 40–50 follicular units per square centimetre reads as convincing coverage.
The estimate is adjusted for your donor area, because donor density sets the ceiling on what is possible. A thin donor area reduces what can safely be harvested, whatever your stage.
Stages 5 and above often need two sessions twelve months apart. Planning that from the start protects your donor area rather than exhausting it in one sitting.
The scale describes male pattern loss. Female pattern loss follows the Ludwig scale, which thins diffusely over the crown while keeping the frontal hairline — a different assessment entirely.
For a graft estimate based on the specific areas you want covered rather than a stage, use the hair graft calculator.
Frequently asked questions
A seven-stage classification of male pattern baldness, first published in the 1970s and still the standard worldwide. It lets a surgeon in Istanbul and a patient in Manchester describe the same pattern without ambiguity.
Pick the higher one. Pattern loss progresses, and planning for where you are heading rather than exactly where you are produces a result that still looks right in five years.
Not necessarily, but it changes what is realistic. At stage 6 or 7 there is simply less donor hair relative to the area needing coverage, so the honest goal becomes a well-designed frame and good density where it matters most, rather than uniform coverage everywhere.
Because donor hair is a finite resource. Two men at the same Norwood stage can have very different donor densities, and the one with a thinner donor area simply cannot safely supply as many grafts. Over-harvesting leaves the back of the head visibly thin, and it cannot be undone.
Yes, unless you treat it. Transplanted hair is permanent, but the untransplanted hair around it carries on thinning. This is why most surgeons recommend finasteride or minoxidil alongside surgery, and why transplanting into an aggressive early pattern is risky.
No. Female pattern loss follows the Ludwig scale — diffuse thinning across the crown with the frontal hairline usually preserved. Women also need a medical assessment first, because thyroid, iron and hormonal causes are common and surgery will not fix them.
It is a planning range, not a measurement. A surgeon counts donor density under magnification and measures the recipient area before giving a firm number. Expect the estimate here to be within a few hundred grafts of the eventual plan for most patients.
Rarely well. Harvesting enough grafts in one sitting to cover that area usually means taking more donor hair than the scalp can afford. Two sessions twelve months apart is the standard approach, and a clinic promising 6,000 grafts in one day is describing a harvest most scalps cannot sustain.
