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Reference

Nine measurements.
And where each number comes from.

These are the only proportions we calculate. Each page states the landmarks behind it, what moves it, and whether its reference range was measured on real people or drawn by a Renaissance artist.

How to read these pages

A measurement describes a photograph. It does not rank a face, and no number here is combined with another to produce a score. Every page carries one of three labels for its reference range, because the ranges are not equally trustworthy and pretending otherwise is the most common failure in this field.

Measured population range
The band comes from published measurements of real people. It describes how the number is distributed, not how it should be. 0 of 9.
Drawing convention
Historical drawing canons provide context for this proportion. We do not display a numerical target band or treat those canons as population norms. 3 of 9.
No reference band
We have not validated a population reference interval for this photographic method. Published anatomical measurements do not automatically validate mesh-based estimates. 6 of 9.

No reference band

Canthal tilt

The angle of the line joining the inner and outer corner of one eye, read against the horizontal. Positive means the outer corner sits higher than the inner corner; negative means it sits lower.

No reference band

Facial width-to-height ratio

Cheekbone-to-cheekbone width divided by the height of the upper face. It is the most studied single ratio in face perception research, and also the most over-read one.

No reference band

Jaw width to cheekbone width

The width of the jaw at the angle of the mandible, divided by the width across the cheekbones. Lower values read as a tapered face, higher values as a squarer one.

No reference band

Midface ratio

The distance from the pupil line down to the mouth, expressed against the distance between the pupils.

Drawing convention

Nose width to eye spacing

The width of the nose at the nostrils, divided by the gap between the inner corners of the eyes. The Renaissance canon holds that the two should be equal.

Drawing convention

Mouth width to nose width

The width of the mouth divided by the width of the nose. The canon sets it at roughly one and a half.

No reference band

Facial index

Face height from the bridge of the nose to the chin, as a percentage of cheekbone width. It is the oldest measurement on this list and the only one with a formal classification attached.

Drawing convention

Upper lip share of lower third

Of the distance from the base of the nose to the chin, the share taken up above the mouth opening. The convention puts it at about a third.

No reference band

Mirrored-landmark deviation

How far paired landmarks sit from their mirror positions about an estimated midline, averaged and expressed as a percentage of interpupillary distance. Zero would be a perfectly mirrored photograph.

The free scanner calculates all nine on your own device. Nothing is uploaded.

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Measurement definitions and reference ranges are read directly from the code that does the calculating, so a page here cannot drift from what the scanner reports. Read the methods and limitations.