Donor area sufficiency determines whether a hair transplant can achieve your coverage goals. The donor area (the back and sides of the scalp) has a finite supply of follicular units, and your graft needs depend on your Norwood stage and the area requiring coverage. This free browser-based tool at myhairline.ai helps you estimate whether your donor supply matches your needs before visiting a clinic.
What Is Donor Sufficiency?
Donor sufficiency measures whether the follicular units available in your safe donor zone are enough to cover your balding areas at adequate density. It is the single most important factor in determining whether a hair transplant will produce a satisfactory result.
The Math Behind Donor Supply
Your donor supply is calculated from three variables:
| Variable | Typical Range | How Measured |
|---|---|---|
| Donor area size | 100-200 cm2 | Physical measurement of safe donor zone |
| Follicular unit density | 120-230 FU/cm2 (varies by ethnicity) | Trichoscopy or clinical estimate |
| Safe extraction limit | 45% maximum | Industry standard to prevent visible donor depletion |
Example calculation: A Caucasian male with 180 cm2 donor area, 200 FU/cm2 density, and 45% safe extraction limit has approximately 16,200 available grafts (180 x 200 x 0.45).
Ethnicity-Based Density Ranges
Follicular unit density varies significantly by ethnicity, directly affecting donor supply:
| Ethnicity | FU Density (per cm2) | Average |
|---|---|---|
| Caucasian | 170-230 | 200 |
| African | 120-180 | 150 |
| Asian | 140-200 | 170 |
| Hispanic | 145-195 | 170 |
| Middle Eastern | 150-210 | 180 |
Note that African hair types typically have more hairs per follicular unit (higher curl pattern provides more visual coverage per graft), partially compensating for lower density.
Graft Requirements by Norwood Stage
Your graft needs depend on your current Norwood stage:
| Norwood Stage | Grafts Needed | Description |
|---|---|---|
| Norwood 2 | 800-1,500 | Slight recession at temples |
| Norwood 3 | 1,500-2,200 | Deep temple recession forming M-shape |
| Norwood 3V | 2,000-2,800 | Temple recession with vertex thinning |
| Norwood 4 | 2,500-3,500 | Further recession with enlarged vertex area |
| Norwood 5 | 3,000-4,500 | Separation between front and vertex narrowing |
| Norwood 6 | 4,000-6,000 | Bridge between areas lost, horseshoe pattern |
| Norwood 7 | 5,500-7,500 | Most extensive hair loss, narrow band remains |
How the Tool Works
The myhairline.ai donor sufficiency assessment uses 468 MediaPipe facial landmarks for precision measurement. The process takes approximately 60 seconds:
Step 1: Upload or Capture Photos
Provide clear photos of:
- Front view: Hairline and temple areas, face centered
- Top view: Crown and vertex area from above
- Donor area: Back of head showing the safe donor zone from ear to ear
Step 2: AI Analysis
The tool automatically:
- Maps your hairline position using facial landmark coordinates
- Estimates your Norwood stage based on recession pattern
- Calculates the area requiring graft coverage
- Estimates your graft requirements based on the Norwood stage detected
Step 3: Sufficiency Report
Your report includes:
- Norwood stage assignment with confidence level
- Estimated graft requirement for full coverage
- Donor supply estimate based on visible donor area characteristics
- Sufficiency ratio: whether estimated supply meets or falls short of needs
- Recommendations for next steps based on your specific results
Interpreting Your Results
| Sufficiency Rating | What It Means | Recommended Action |
|---|---|---|
| High sufficiency (supply exceeds need by 50%+) | Donor area can comfortably cover all balding areas | Proceed to clinic consultation for detailed planning |
| Adequate sufficiency (supply meets need) | Coverage is achievable but with limited reserve | Discuss strategic graft distribution with surgeon |
| Borderline sufficiency (supply slightly below need) | Full coverage may require compromise on density | Consider combination approach: transplant + medication |
| Insufficient (supply significantly below need) | Donor cannot cover all balding areas adequately | Explore partial coverage, SMP, or non-surgical alternatives |
Why Donor Assessment Matters Before a Clinic Visit
Many patients visit clinics without understanding their donor limitations. This leads to:
- Unrealistic expectations about coverage density
- Surprise when surgeons recommend fewer grafts than expected
- Poor planning for future hair loss progression (your Norwood stage may advance, requiring more grafts later)
- Risk of over-harvesting if a clinic prioritizes immediate results over long-term donor health
The safe extraction limit of 45% exists to prevent visible donor thinning. Clinics that exceed this threshold may produce short-term results at the cost of noticeable donor depletion.
Factors the Tool Cannot Measure
While the AI assessment provides valuable estimates, certain factors require in-person clinical evaluation:
- Scalp laxity: Affects FUT strip width and total graft yield
- Hair caliber: Thicker individual hairs provide more visual coverage per graft
- Hair color vs. skin contrast: Low contrast (blond hair on light skin) requires fewer grafts for the same visual density
- Body hair availability: Beard and chest hair can supplement scalp donor in some cases
- Miniaturization percentage: Requires trichoscopic measurement in clinic
Try the Assessment Now
Get your free donor sufficiency estimate at myhairline.ai/analyze. No account required, no data stored, and results in 60 seconds from any browser.
For more context on how staging works, read the Norwood Scale complete guide. To understand the full AI analysis capabilities, visit the AI hair loss analysis tool page.
Medical disclaimer: This tool provides estimates for informational purposes only. Donor area sufficiency must be confirmed by an in-person clinical examination with a qualified hair restoration surgeon. Actual graft yield, density, and surgical outcomes depend on individual anatomy and surgical technique.