Measurement reference · FaceFluent editorial · September 13, 2026

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.

Educational method only. Personal numerical values are currently unavailable in the free preview and reports under the current offer. Existing purchases retain their purchased scope.

Illustrative facial landmark visualization — Landmark illustration. The calculation and its limitations are described below.

Also called naso-oral ratio, mouth width to nose width.

Reference range

None.

Historical drawing canons provide context for this proportion. We do not display a numerical target band or treat those canons as population norms.

How we calculate it

Distance between the two mouth-corner landmarks over the distance between the two nostril-edge landmarks.

What moves the number

Expression, more than anything. A closed neutral mouth and a slight smile give different answers on the same face in the same minute.

What it cannot tell you

Again a convention rather than a norm. The same 1985 survey found the horizontal canons matched a minority of real faces. A difference from that convention does not establish that a mouth is too wide or too narrow.

References

Farkas LG, Hreczko TA, Kolar JC. Vertical and horizontal proportions of the face in young adult North American Caucasians: revision of neoclassical canons. Plast Reconstr Surg, 1985.

Another drawing convention with a figure attached. The figure came from illustration, not from measuring people.

Read: Mouth width, nose width, and the number one and a half

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This page is educational. It is not a clinical assessment, a diagnosis, or a claim about how you look. Read the methods and limitations.