Interpupillary-Mouth Width Ratio: What It Measures and How to Read It | FaceIQ Labs

Key facts

• Calculation: mouth-corner width divided by interpupillary distance, even though the report label names the pupil term first.
• Below 1 means the mouth is narrower than pupil spacing; above 1 means the mouth is wider than pupil spacing.
• Worked example: a 54-unit mouth with pupils 64 units apart gives 0.84; at 60 units of mouth width it becomes 0.94.
• The example values explain the calculation and are not a target range.
• It is a front-view Harmony measurement in the mouth region.
• It complements the Mouth-to-Nose Width Ratio by using an upper-face reference (the pupils) instead of the nose.
• FaceIQ Labs calls it a FaceIQ adaptation: a landmark-based description of facial shape. The linked research has not directly validated this exact formula or its score.
• A smiling photo changes the numerator, and eyes looking away can change the pupil reference.
• Harmony is weighted roughly 60% from the front photo and 40% from the side photo, and FaceIQ Labs measures 70+ facial ratios and angles in total.

How does FaceIQ Labs calculate the Interpupillary-Mouth Width Ratio?

FaceIQ Labs calculates the Interpupillary-Mouth Width Ratio as mouth-corner width divided by interpupillary distance, the spacing between the pupils. The report label names the pupil term first, but the mouth is the numerator. It is a front-view Harmony measurement in the mouth region of the face.

What does a result above or below 1 mean?

For FaceIQ Labs' Interpupillary-Mouth Width Ratio, a result below 1 means the mouth is narrower than the spacing between the pupils, and a result above 1 means the mouth is wider than pupil spacing. The ratio compares the horizontal scale of the mouth with that of the eyes.

Is there an ideal value for the Interpupillary-Mouth Width Ratio?

FaceIQ Labs' guide to the Interpupillary-Mouth Width Ratio does not state a target or ideal value. Its example numbers, 0.84 and 0.94, only illustrate the calculation. FaceIQ Labs says its score weights and reference ranges are model settings, and that the cited research does not collectively validate the scoring system.

Why does FaceIQ Labs include this ratio in Harmony?

FaceIQ Labs includes the Interpupillary-Mouth Width Ratio because it compares the horizontal scale of the mouth and eyes. It complements the Mouth-to-Nose Width Ratio by using an upper-face reference, the pupils, instead of the nose. It is one of the 70+ ratios and angles measured in the Harmony pillar.

What does a worked example of the ratio look like?

FaceIQ Labs gives this example for its Interpupillary-Mouth Width Ratio: a mouth 54 units wide with pupils 64 units apart gives 0.84. With a mouth 60 units wide, the ratio becomes 0.94. FaceIQ Labs states these values explain the calculation, are not a target range, and are not measurements of its schematic.

What can change my Interpupillary-Mouth Width Ratio result?

For FaceIQ Labs' Interpupillary-Mouth Width Ratio, a smiling photo changes the mouth-width numerator, and eyes looking away can change the pupil-spacing reference. For accuracy, FaceIQ Labs recommends photos taken from six feet away with the back camera at 2x zoom, at eye level, with even lighting and a neutral expression.

Where does the Interpupillary-Mouth Width Ratio come from?

FaceIQ Labs describes the Interpupillary-Mouth Width Ratio as a FaceIQ adaptation: a landmark-based description of facial shape. The linked research gives background on facial measurement or perception, but it has not directly validated this exact formula or its score. Its score weights and reference ranges are model settings.

What research does FaceIQ Labs cite for this ratio?

FaceIQ Labs cites one source for the Interpupillary-Mouth Width Ratio: Pallett, Link and Lee (2010), 'New "Golden" Ratios for Facial Beauty.' Four experiments varied eye spacing and eye-to-mouth distance in face images, and preferences depended on feature arrangement. The tested ratios and stimuli do not validate every FaceIQ measurement or a universal ideal.

Which other FaceIQ Labs guides cover the mouth region?

• Lip Thickness
• Lower Lip to Upper Lip Ratio
• Cupid's Bow Depth
• Mouth-to-Nose Width Ratio (a complementary measure that also looks at mouth width, compared with the nose)
• Mouth Corner Position
• Chin-to-Philtrum Ratio

Frequently asked questions

Is the Interpupillary-Mouth Width Ratio mouth width over pupil spacing, or the reverse?

FaceIQ Labs calculates it as mouth-corner width divided by interpupillary distance, even though the label names the interpupillary term first.

What does it mean if my ratio is above or below 1?

Below 1 means the mouth is narrower than the distance between the pupils. Above 1 means the mouth is wider than pupil spacing.

Is this ratio validated by the research FaceIQ Labs cites?

No. FaceIQ Labs says the linked research gives background on facial measurement or perception but has not directly validated this exact formula or its score.

Which other FaceIQ Labs measurement is related to this ratio?

The Mouth-to-Nose Width Ratio. It also looks at mouth width, but compares it to the nose, while the Interpupillary-Mouth Width Ratio uses pupil spacing as an upper-face reference.

Why might my ratio differ between photos?

Smiling changes the mouth-width numerator, and eyes looking away from the camera can change the pupil-spacing reference.