Donor density below 60 FU/cm2 limits the available graft count and can disqualify a patient from hair transplantation entirely. AI density measurement of your donor area identifies this constraint before you book surgery, saving you time and money while setting realistic expectations for what a transplant can achieve.
Why Donor Density Matters
Every hair transplant moves follicles from the donor zone (the permanent horseshoe-shaped band at the back and sides of the head) to the thinning recipient area. The number of grafts available depends on two factors:
- Donor density: How many follicular units exist per cm2 in your donor area
- Safe extraction limit: How many of those follicles can be removed without creating visible donor thinning
The safe extraction limit is approximately 45% of total donor follicles. Taking more than this percentage creates noticeable thinning in the donor zone, which defeats the purpose of the procedure.
| Ethnicity | Average Donor Density (FU/cm2) | Total Donor Area (~200 cm2) | Safe Extraction (45%) |
|---|---|---|---|
| Caucasian | 170 to 230 | 34,000 to 46,000 FU | 15,300 to 20,700 grafts |
| Asian | 140 to 200 | 28,000 to 40,000 FU | 12,600 to 18,000 grafts |
| African | 120 to 180 | 24,000 to 36,000 FU | 10,800 to 16,200 grafts |
| Hispanic | 145 to 195 | 29,000 to 39,000 FU | 13,050 to 17,550 grafts |
| Middle Eastern | 150 to 210 | 30,000 to 42,000 FU | 13,500 to 18,900 grafts |
These numbers reveal why donor density assessment matters. A Norwood 5 patient needs 3,000 to 4,500 grafts. If their donor density supports 15,000+ safe extractions, they have plenty of supply. But if their donor density is below average, they may only have enough for one session, making graft allocation strategy critical.
Step 1: Photograph Your Donor Area
For the most accurate density reading, prepare and photograph your donor area carefully.
Ideal preparation: Clip or buzz the donor zone to 1 to 2mm length. Short hair allows the AI to count individual follicular units with maximum accuracy. If you are not comfortable buzzing, pull the hair tight against the scalp or have someone hold it flat.
Photo angles (take all three):
- Posterior (back of head): Stand with your back to the camera. The photographer should be at the same height as the back of your head, approximately 8 to 12 inches away.
- Left lateral: Turn your head 90 degrees to the right so the camera captures the left side of your donor zone.
- Right lateral: Turn your head 90 degrees to the left for the right side.
Lighting: Use bright, even overhead lighting. Avoid direct flash, which creates glare spots that obscure follicle visibility. Natural daylight from a window works well if the light is diffused.
Step 2: Upload and Analyze
Upload your donor area photos to myhairline.ai. The density analysis provides:
- FU/cm2 estimate: The number of follicular units per square centimeter in each photographed zone
- Density classification: Whether your donor density falls in the low, average, or high range for your demographic
- Estimated total supply: Calculated total available grafts based on your density and the 45% safe extraction limit
Record these numbers. They become the foundation for every transplant planning conversation.
Step 3: Calculate Your Graft Budget
Your graft budget is the total number of grafts you can safely extract across your lifetime. This is not just about one surgery. If you are young and still progressing, you may need additional procedures in the future.
Here is how to calculate it:
Your donor density (FU/cm2) x total donor area (approximately 200 cm2) x 0.45 (safe extraction rate) = lifetime graft budget
For example: 180 FU/cm2 x 200 cm2 x 0.45 = 16,200 total lifetime grafts available.
Now compare that to your current and projected needs:
| Norwood Stage | Grafts Needed | Remaining After Surgery |
|---|---|---|
| Norwood 2 | 800 to 1,500 | 14,700 to 15,400 |
| Norwood 3 | 1,500 to 2,200 | 14,000 to 14,700 |
| Norwood 3V | 2,000 to 2,800 | 13,400 to 14,200 |
| Norwood 4 | 2,500 to 3,500 | 12,700 to 13,700 |
| Norwood 5 | 3,000 to 4,500 | 11,700 to 13,200 |
| Norwood 6 | 4,000 to 6,000 | 10,200 to 12,200 |
| Norwood 7 | 5,500 to 7,500 | 8,700 to 10,700 |
If your projected Norwood progression could reach Stage 6 or 7, and your lifetime budget is 12,000 grafts, your surgeon needs to plan graft allocation strategically across multiple potential sessions rather than using the maximum in a single procedure.
Step 4: Discuss Findings With Your Surgeon
Arriving at your transplant consultation with donor density data gives your surgeon a head start. Typically, the surgeon performs a manual density assessment during the consultation using a handheld densitometer or loupe magnification. Your AI-generated density data provides a preliminary reading that covers approximately 80% of the information the surgeon needs for initial planning.
Key questions to ask using your data:
- "My donor density measures approximately [X] FU/cm2. Does your manual assessment match this?"
- "Given my density and current Norwood stage, how many grafts would you allocate to this session?"
- "What is your recommended graft reserve for potential future sessions?"
- "Do you recommend FUE or FUT based on my donor characteristics?"
FUE (Follicular Unit Extraction) harvests individual follicles leaving small dot scars, with 7 to 10 days recovery. FUT (strip method) removes a tissue strip with a linear scar, with 10 to 14 days recovery. Both achieve 90 to 95% graft survival rates. Your donor density and hair characteristics influence which method your surgeon recommends.
Step 5: Track Donor Area Post-Surgery
After a transplant, continue tracking your donor area density. This serves two purposes:
- Healing verification: Confirm that donor density stabilizes after extraction and the area heals without excessive thinning
- Future planning: Monitor for any progressive thinning in the donor zone (rare but possible in aggressive androgenetic alopecia) that could affect future session planning
Monthly donor area scans for the first 6 months post-surgery, then quarterly afterward, provide a comprehensive donor health record.
Cost Context by Region
Knowing your graft budget helps estimate total procedure cost by region:
| Region | Cost Per Graft (USD) | 3,000-Graft Procedure |
|---|---|---|
| USA | $4 to $6 | $12,000 to $18,000 |
| UK | $3 to $5 | $9,000 to $15,000 |
| Europe | $2.50 to $4.50 | $7,500 to $13,500 |
| Turkey | $1 to $2 | $3,000 to $6,000 |
| India | $0.50 to $1.50 | $1,500 to $4,500 |
| Thailand | $1.50 to $3 | $4,500 to $9,000 |
| Mexico | $2 to $4 | $6,000 to $12,000 |
Read more about the full hair transplant decision and recovery guide and graft count estimation tracking.
Start your donor density assessment with a free scan at myhairline.ai/analyze.
Medical disclaimer: This article is for informational purposes only and does not constitute medical advice. Donor density assessment via photography provides an estimate, not a clinical measurement. A board-certified hair transplant surgeon should perform an in-person evaluation before any surgical planning decisions are made.