Facial ThirdsHow AI measures this feature and photo tips
Classical proportion divides the face into three equal vertical zones: upper (hairline to brows), middle (brows to nose base), and lower (nose base to chin). Deviations signal unique character and affect harmony scores.
See this feature in action with our Face Analyser, Face Shape Analyzer, or Guess My Age.
Key Characteristics
- ✦Upper third: forehead height
- ✦Middle third: eye-to-nose span
- ✦Lower third: mouth-to-chin distance
- ✦Golden ratio approximations in idealised models
- ✦Ethnic and individual variation is normal
Analysis & Photo Tips
- 📸Pull hair back to expose true hairline
- 📸Neutral expression for accurate measurement
- 📸Front-facing, level camera essential
- 📸Compare thirds rather than absolute measurements
Related Features
Forehead
Forehead height and width define the upper third of the face. A wide or high forehead influences heart and oval classifications, while a narrow forehead characterises triangle and some diamond shapes.
Nose
The nose anchors midface proportion — its width, length, and projection balance the eyes and mouth. Nasal geometry interacts with facial thirds and contributes to profile harmony in AI analysis.
Chin
Chin projection, width, and shape define the lower face terminus. Pointed chins characterise heart faces; wide chins suggest square or triangle shapes; recessed chins affect profile balance.
Facial Symmetry
Facial symmetry measures left-right correspondence of landmarks — eyes, brows, nostrils, lip corners, and jaw contour. Near-symmetry correlates with higher harmony scores, though perfect symmetry is rare and unnatural.
FAQ — Facial Thirds
What are the facial thirds?
The face divided into three horizontal sections of roughly equal height: forehead, midface (eyes and nose), and lower face (mouth and chin).
Are equal thirds ideal?
Classical art favours near-equal thirds, but modern attractiveness research emphasises overall harmony over strict mathematical equality.
How does AI use facial thirds?
Smile Tracker maps landmarks to compute third ratios and includes them in facial proportion scoring.