Mouth width : face
Your mouth width relative to your face width.
Why it matters
Mouth width anchors the lower face; corners reaching toward the iris lines is a common harmony reference.
What mouth width to face width means
This metric divides the width of your mouth, corner to corner, by the width of your face measured across the cheekbones (the bizygomatic width). It places the mouth in the context of the whole face rather than judging it in isolation, asking how wide the mouth is for the face that frames it.
A long-standing visual reference, noted in the existing guidance, is that the corners of a relaxed mouth tend to fall roughly beneath the inner edges of the irises. On this tool the measured value sits around 0.37 of the face width, drawing on the anthropometric work of Farkas 1994.
Why mouth width anchors the lower face
The mouth is the visual centre of gravity of the lower face, so its width sets a lot of the balance there. A mouth proportionate to the cheekbones looks settled; one that reads narrow can make the lower face look pinched, while a very wide mouth pulls attention outward. Because the reference is to the corners and the iris lines, this is fundamentally a horizontal harmony cue across the lower face.
Mouth width also interacts with the features around it. The same mouth can read as wide on a narrow face or modest on a broad one, which is exactly why this metric uses face width as the denominator rather than reporting the mouth in millimetres. It is the relationship that the eye picks up on, not the raw size.
The typical range and honest caveats
The tool treats roughly 0.36 to 0.42 of the face width as the balanced band, with typical faces near 0.37. This comes from neoclassical and anthropometric convention rather than any objective standard, and the iris-line reference is a rule of thumb, not a measured law. Mouth width relative to face varies between individuals and across populations, so the band is a guide, not a boundary.
Two practical sources of noise: a smile widens the mouth and inflates the ratio, and any head turn distorts horizontal measurements. A relaxed mouth and a square, front-on photo give the most reliable figure.
Interpreting your value and what can shift
Read the number as a placement, not a pass or fail. Inside the band means your mouth width suits your face; below or above means it reads relatively narrow or wide. Confirm the photo conditions before drawing conclusions, since expression and angle move this metric easily.
Mouth width is largely set by structure, the soft tissue and the bone it sits over, and it does not change with effort. The reversible lever is cosmetic: lip makeup that over-lines or under-lines the corners can adjust the apparent width a little for a given look. Beyond that, this is best understood as fixed anatomy described in relation to the rest of the face.
Typical range
~0.36-0.42 of face width
Width of the mouth relative to face width. Classically the mouth spans the gap between the irises.
What your reading means
- Typical
- Your mouth width suits your face.
- Less common
- Your mouth width is slightly narrow or wide.
- Distinctive
- Your mouth reads relatively narrow or wide for your face.
How we measured it
We divide your mouth width by your cheekbone width.
The evidence
mouthWidthFace.caveat
References
- Farkas, L. G. (Ed.). (1994). Anthropometry of the Head and Face (2nd ed.). New York: Raven Press.