Fitzpatrick Skin Type Calculator

The Fitzpatrick scale classifies skin by one thing only: how it responds to ultraviolet light. Thomas Fitzpatrick, a Harvard dermatologist, published it in 1975 because he needed a way to predict how patients would react to the UV doses used in psoriasis phototherapy. Guessing from appearance was getting people burned. The scale is still the standard for setting phototherapy doses, laser settings, and skin cancer risk stratification.

The six phototypes:

• Type I: Always burns, never tans. Very fair, often freckled, red or light blond hair.
• Type II: Usually burns, tans minimally. Fair, commonly blue or green eyes.
• Type III: Sometimes burns, tans gradually. Medium, any eye colour.
• Type IV: Rarely burns, tans easily. Olive to light brown.
• Type V: Very rarely burns, tans darkly. Brown.
• Type VI: Never burns, deeply pigmented. Dark brown to black.

How the score works

The full Fitzpatrick questionnaire asks ten questions about genetic traits and sun response, each scored 0 to 4, and sorts the total out of 40 into six bands. This calculator is a shortened version. It asks four of those questions, eye colour, natural hair colour, burn-versus-tan response and freckling on skin that rarely sees the sun, and scales the bands down to a total out of 16. That last question is the tell people forget, and it is why it specifies unexposed areas. Freckles that only appear after a summer are sun damage; freckles on your back in February are genetic, and they point hard toward Type I or II.

Worked example

Blue eyes (1), blond hair (1), usually burns and tans minimally (1), several freckles on unexposed skin (1). Total 4, which lands in the 3 to 5 band: Type II. SPF 30 is the floor dermatologists set for everyone, and at this phototype a 50 gives useful margin. Unprotected, Type II skin reddens in about 17 minutes at UV 10, a strong summer noon, using the same burn model as the site’s UV Safe Sun Time calculator.

What the type does and does not tell you

It predicts burn risk, not cancer immunity. Melanin in Type V and VI skin gives an intrinsic sun protection factor of only about 13, nowhere near enough on its own, and skin cancer in darker skin is diagnosed later and carries worse outcomes precisely because it is assumed not to happen. Everyone needs SPF 30 or higher. The scale also handles mixed heritage poorly, since it was built around a fairly narrow population, so treat a borderline score as a range rather than a verdict.

Answer for your natural, untanned state. A summer tan will push your score two or three points high and hand you the wrong advice for next spring.