Harmony & facial ratios
Interpupillary-Mouth Width Ratio
1 min read · Updated October 4, 2026
The width of the mouth compared with the distance between your pupils.
What it is
This relates the lower face to the eyes. It divides the width of the mouth by the distance between the pupils, so it shows whether the mouth is narrow or wide relative to the eye line.
How it's measured
Mouth width between the two corners is divided by pupil distance, both taken in a levelled frame.
How it's read
On most faces the mouth is somewhat narrower than the pupil gap, at about four fifths of it. A noticeably higher figure means a wide mouth for the eye spacing, and a lower one a small mouth.
What affects it
As with every mouth ratio, expression is the main distortion. A relaxed, closed mouth gives a repeatable result, and shooting from a normal distance avoids wide-angle stretching.
Related measurements
In the same group: Lower Lip to Upper Lip Ratio, Cupid's Bow Depth and Mouth Corner Position. The full list is on the Harmony overview.
See it on a full report
Open the sample report to see every measurement, score and highlight on a real example.