MASI (Melasma Area and Severity Index)
Melasma Area and Severity Index (Kimbrough-Green 1994): forehead, right malar, left malar (each x 0.3) and chin (x 0.1), scoring Area (0-6) and Darkness + Homogeneity (0-4) per region; range 0-48, higher = more severe.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Forehead — Area
- 4
- Forehead — Darkness
- 2
- Forehead — Homogeneity
- 2
- Right malar — Area
- 3
- Right malar — Darkness
- 2
- Right malar — Homogeneity
- 1
- Left malar — Area
- 3
- Left malar — Darkness
- 2
- Left malar — Homogeneity
- 1
- Chin — Area
- 2
The other 2 values
- Chin — Darkness
- 1
- Chin — Homogeneity
- 1
Result: Melasma Area and Severity Index 10.6 of 48 — higher = more severe.
The tool opens with these values already filled in. Replace them with your own.
What the result means
- 0-48
- Continuous severity index (forehead/right malar/left malar x 0.3, chin x 0.1; Area 0-6, Darkness + Homogeneity 0-4). Higher = more severe. No official bands. A grading index, not a diagnosis.
What you enter
- Forehead — Area (0-6)
- Forehead — Darkness (0-4)
- Forehead — Homogeneity (0-4)
- Right malar — Area (0-6)
- Right malar — Darkness (0-4)
- Right malar — Homogeneity (0-4)
- Left malar — Area (0-6)
- Left malar — Darkness (0-4)
- Left malar — Homogeneity (0-4)
- Chin — Area (0-6)
The other 2 fields
- Chin — Darkness (0-4)
- Chin — Homogeneity (0-4)
How this is calculated
Kimbrough-Green CK, Griffiths CE, Finkel LJ, et al. Topical retinoic acid (tretinoin) for melasma in black patients. Arch Dermatol. 1994;130(6):727-733. (MASI; validation Pandya AG, et al. J Am Acad Dermatol. 2011;64(1):78-83.) Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.