# Interpupillary-Mouth Width Ratio

Harmony · Front view · Mouth · https://www.faceiqlabs.com/support/harmony/interpupillary-mouth-width-ratio

Mouth width divided by pupil spacing, despite the order in the report label.

## What is measured

Calculation: Mouth-corner width ÷ interpupillary distance

## Why it matters

It compares the horizontal scale of the mouth and eyes. It complements mouth-to-nose width by using an upper-face reference instead of the nose.

- Below 1: the mouth is narrower than pupil spacing.
- Above 1: the mouth is wider than pupil spacing.

## Where the idea comes from

Evidence: FaceIQ adaptation. This is a FaceIQ landmark-based description of facial shape. The linked research provides background on facial measurement or perception; it has not directly validated this exact formula or its score.

## A worked example

A mouth 54 units wide with pupils 64 units apart gives 0.84. At 60 units of mouth width, it becomes 0.94.

Example values explain the calculation. They are not a target range.

## How to read your result

A smiling photo changes the numerator. Eyes looking away can change the pupil reference.

## Research & further reading

These sources explain the history or related evidence. FaceIQ’s score weights and reference ranges are model settings; the papers do not collectively validate the scoring system.

- Pallett, Link & Lee (2010). [New “Golden” Ratios for Facial Beauty](https://pmc.ncbi.nlm.nih.gov/articles/PMC2814183/). Four experiments varied eye spacing and eye-to-mouth distance in face images. Preferences depended on feature arrangement. The tested ratios and stimuli do not validate every FaceIQ measurement or a universal ideal.

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Source: https://www.faceiqlabs.com/support/harmony/interpupillary-mouth-width-ratio · FaceIQ Labs overview for AI assistants: https://www.faceiqlabs.com/llms.txt