SALT (Severity of Alopecia Tool)
Severity of Alopecia Tool (Olsen 2004): % terminal hair loss per scalp region weighted top 0.40, back 0.24, right 0.18, left 0.18; range 0-100 with S0-S5 bands.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Top of scalp — % hair loss
- 50 %
- Back of scalp — % hair loss
- 50 %
- Right side — % hair loss
- 50 %
- Left side — % hair loss
- 50 %
Result: Severity of Alopecia Tool 50 of 100 — S3 (50-74%).
The tool opens with these values already filled in. Replace them with your own.
What the result means
- S0-S2 (0-49)
- No to moderate scalp hair loss.
- S3-S5 (50-100)
- Extensive to total scalp hair loss (top 0.40, back 0.24, sides 0.18 each; only terminal hair counts). A severity tool, not a diagnosis.
What you enter
- Top of scalp — % hair loss
- Back of scalp — % hair loss
- Right side — % hair loss
- Left side — % hair loss
How this is calculated
Olsen EA, Hordinsky MK, Price VH, et al. Alopecia areata investigational assessment guidelines—Part II. J Am Acad Dermatol. 2004;51(3):440-447. Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.