1. Grafts, follicular units and hairs
Hair grows out of the scalp in natural clusters called follicular units (FU), each holding one to four hairs. A graft is one transplanted follicular unit. That is why a quote for 2,000 grafts usually moves roughly 4,000–5,000 individual hairs.
Always confirm whether a clinic prices per graft or per hair — the same procedure can look twice as cheap when quoted per hair.
2. Typical graft ranges by zone
Surgeons plan a transplant zone by zone, because each area has a different surface area and a different visual priority. These are widely used planning ranges, not a prescription:
| Zone | Typical grafts | Notes |
|---|---|---|
| Frontal hairline | 800–1,500 | Highest visual impact; needs single-hair FUs in front |
| Midscalp | 700–1,500 | Bridges hairline to crown; medium density is usually enough |
| Crown / vertex | 1,000–2,000 | Whorl pattern makes coverage expensive per cm² |
| Full pattern (all zones) | 3,500–5,000 | Often staged across two sessions |
3. Density: what FU/cm² means
Density is measured in follicular units per square centimetre. Untouched scalp sits around 80–100 FU/cm². Transplants rarely aim for that: 35–45 FU/cm² in the hairline and 25–35 FU/cm² in the midscalp typically look natural, because overlapping hair shafts shadow the skin underneath.
Coverage also depends on hair calibre and colour contrast with your skin. Thick, light hair on light skin covers far better than fine, dark hair on pale skin at the same graft count.
4. Donor area limits
The safe donor zone at the back and sides of the scalp is finite — commonly 5,000–7,000 grafts over a lifetime. Over-harvesting thins the donor permanently and limits future sessions, so a good plan spends grafts where they matter visually first, usually the hairline and midscalp before the crown.
5. How an AI photo estimate works
A photo-based estimate segments the scalp into hairline, midscalp, crown and donor regions, reads visible follicle spacing and scalp show-through in each region, and converts that into a graft range plus a density figure. Confidence rises with more views: a top-down crown photo and a donor shot materially improve the read compared with a single front-facing image.
Treat the output as a planning range with an explicit confidence level, then verify it with a surgeon who can measure donor density under magnification.
6. Questions to ask your clinic
- How many grafts per zone, and what target density in FU/cm²?
- Is the quote per graft or per hair, and what is included?
- What is my measured donor density and estimated lifetime graft supply?
- Who performs the extraction and implantation — the surgeon or technicians?
- Can I see before/after photos of patients with my hair type and pattern?
7. Frequently asked questions
- How many grafts do I need for a hair transplant?
- Most hairline-only cases use 1,500–2,500 follicular units, a hairline plus midscalp case typically needs 2,500–3,500, and adding the crown often pushes the total to 3,500–5,000. The exact number depends on the recession pattern, the density you want and how much donor hair is available.
- What is a follicular unit versus a hair?
- A follicular unit is a natural grouping of 1–4 hairs. Clinics quote grafts (follicular units), so 2,000 grafts usually means roughly 4,000–5,000 individual hairs.
- What density is considered natural?
- Native scalp density is around 80–100 FU/cm². A transplant that reaches 35–45 FU/cm² in the hairline generally reads as natural because hair shafts overlap and shadow the scalp.
- Can an AI photo scan replace a clinic consultation?
- No. A photo-based estimate is a planning tool: it gives you a graft range, a density read and a visual preview so you can compare quotes. Donor calibre, scalp laxity and medical history still need an in-person exam.