Harmony · Front view · Mouth
Chin-to-Philtrum Ratio
The span below the lower lip compared with the span between the nose base and upper lip.
What is measured
The calculation
Lower-lip-to-chin height ÷ nasal-base-to-Cupid’s-bow height
Front view / Measurement guide
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Why it matters
This compares two vertical spaces around the lips. A tall chin region and a short philtrum can both increase the number; neither follows from the ratio alone.
- Lower: less chin-region height relative to philtrum height.
- Higher: more chin-region height relative to philtrum height.
Where the idea comes from
FaceIQ adaptation
Subdividing the lower face develops the classical proportion approach. FaceIQ uses the lower-lip edge and Cupid’s bow as the inner endpoints, which should be checked before comparing with another measurement method. [1]
A worked example
A 32-unit lower-lip-to-chin span and 14-unit philtrum give 2.29. A 16-unit philtrum lowers the ratio to 2.0.
Example values explain the calculation. They are not a target range and are not measurements of the schematic above.
Research & further reading
The sources below explain the history or related evidence. FaceIQ’s score weights and reference ranges are model settings; these papers do not collectively validate the scoring system.
[1] Farkas et al. · 1985
Vertical and horizontal proportions of the face: revision of neoclassical canonsTested nine traditional proportion rules against measured faces. Useful history for facial thirds and width comparisons; classical rules are not universal targets.