Lip RatioHow AI measures this feature and photo tips
Lip ratio compares upper to lower lip fullness and mouth width relative to nose width. The 1:1.6 upper-to-lower ratio appears frequently in beauty research, though individual variation is substantial.
See this feature in action with our Face Analyser, Face Shape Analyzer, or Guess My Age.
Key Characteristics
- ✦Upper vs lower lip volume
- ✦Cupid's bow definition
- ✦Mouth width vs nose width
- ✦Philtrum length above upper lip
- ✦Smile-induced lip stretch changes ratio
Analysis & Photo Tips
- 📸Relaxed lips for resting ratio
- 📸Smile photos show different proportions
- 📸Front-facing, mouth closed for baseline
- 📸Macro lens distortion affects lip appearance
Related Features
Lips
Lips are key expressive features affecting smile scoring, perceived warmth, and lower-face proportion. Fullness, symmetry, and smile dynamics all feed into Smile Tracker's blendshape and landmark analysis.
Nose-to-Mouth Ratio
The nose-to-mouth ratio compares nasal width to mouth width and the vertical distance between nose base and upper lip. Balanced ratios contribute to lower-third harmony in facial proportion scoring.
Lip Ratio
Lip ratio compares upper to lower lip fullness and mouth width relative to nose width. The 1:1.6 upper-to-lower ratio appears frequently in beauty research, though individual variation is substantial.
FAQ — Lip Ratio
What is the ideal lip ratio?
Studies often cite a 1:1.6 upper-to-lower lip ratio as aesthetically balanced, though preferences vary culturally and individually.
Do lips thin with age?
Yes. Collagen loss and volume depletion reduce lip fullness — a visible signal in age estimation models.
How does smiling change lip ratio?
Smiling stretches the mouth horizontally and can thin the upper lip visually, temporarily altering measured ratios.