Facial index
Morphological face height : bizygomatic width
How long the face is compared with how wide it is: the height from the bridge of the nose between the eyes down to the bottom of the chin, divided by the width across the cheekbones.
Also searched as face length to width, long face, wide face and morphological face index.
How to read it
the face is broad relative to its height for the reference group.
face height relative to width sits close to the reference mean.
the face is long relative to its width for the reference group.
Bizygomatic width from a 2D photo carries a systematic ~3.3 mm bias versus direct caliper measurement (Lim 2022) and shifts with yaw. Treat the width term as approximate.
Reference values by population
| Reference population | Female (mean ± SD) | Male (mean ± SD) | n | Source |
|---|---|---|---|---|
| North American White | 0.855 ± 0.054 | 0.872 ± 0.059 | 2326 | Farkas 1994/2005 (NA White young adults) prov. |
| East Asian | 0.809 ± 0.055 | 0.828 ± 0.055 | 618 | Farkas 2005 (Chinese/Japanese/Vietnamese/Thai pooled); Jayaratne 2012 (Southern Chinese, n=103) prov. |
| South Asian | 0.852 ± 0.058 | 0.868 ± 0.06 | 210 | Farkas 2005 (Indian); Metgudmath 2022 prov. |
| African / African diaspora | 0.856 ± 0.058 | 0.871 ± 0.059 | 300 | Farkas 2005 (African-American, Zulu, Angolan) prov. |
| Middle Eastern | 0.869 ± 0.056 | 0.884 ± 0.06 | 348 | Farkas 2005 (Turkish, Iranian, Egyptian); Al-Sebaei 2015 (Saudi, n=168) prov. |
| Hispanic / Latino | 0.832 ± 0.056 | 0.843 ± 0.058 | 120 | Farkas 2005 (Mexican-American) prov. |
| Not specified — show pooled | 0.845 ± 0.06 | 0.861 ± 0.062 | 3922 | Unweighted pool of the six groups above prov. |
Where these numbers come from
Transcribed from the cited anthropometric literature; SDs of ratios are propagated conservatively (independence assumed). Entries marked prov. await line-by-line audit against the primary tables. See the norm provenance note.
Why every value has an error bar
Every value Canthion reports carries a 1σ uncertainty propagated from MediaPipe Face Mesh's published accuracy (3.96% of inter-ocular distance mean absolute error per landmark, Kartynnik 2019). On a typical photo with 300 px between the pupils, that is about 12 px of wander on every point. Small ratios and angles inherit it, so their intervals are wide. A number without an interval is a number pretending to be more precise than it is.
References
- Farkas, Katic & Forrest (2005). International Anthropometric Study of Facial Morphology in Various Ethnic Groups/Races. J Craniofac Surg 16(4):615–646. doi.org/10.1097/01.SCS.0000171847.58031.9E
- Lim, Abdul Shakor & Shaharudin (2022). Reliability and Accuracy of 2D Photogrammetry: A Comparison With Direct Measurement. Front Public Health 9:813058. doi.org/10.3389/fpubh.2021.813058
Common questions
What is facial index?
How long the face is compared with how wide it is: the height from the bridge of the nose between the eyes down to the bottom of the chin, divided by the width across the cheekbones. Higher values = longer/narrower face (leptoprosopic); lower = broader (euryprosopic).
How is facial index measured from a photo?
It is computed from the face-mesh landmarks (n, me, zy_R, zy_L): dist(n, me) / dist(zy_R, zy_L). Every value carries a 1σ error bar propagated from the landmark detector's published accuracy, with a floor of ± 0.03, so a small difference inside the interval is not a difference.
What is a normal facial index?
Reference means and standard deviations from the anthropometric literature, by population. North American White: 0.855 ± 0.054 for women, 0.872 ± 0.059 for men; East Asian: 0.809 ± 0.055 for women, 0.828 ± 0.055 for men; South Asian: 0.852 ± 0.058 for women, 0.868 ± 0.06 for men; African / African diaspora: 0.856 ± 0.058 for women, 0.871 ± 0.059 for men. This value is provisional and awaits line-by-line audit against the primary tables. Your own value is placed on the distribution you choose, as a percentile with its error bar.
What does a low or high facial index mean?
Below the mean: the face is broad relative to its height for the reference group. Above the mean: the face is long relative to its width for the reference group.
How reliable is facial index from a photograph?
Bizygomatic width from a 2D photo carries a systematic ~3.3 mm bias versus direct caliper measurement (Lim 2022) and shifts with yaw. Treat the width term as approximate.
Length-to-width is one of the five inputs the face-shape read is built from.
Related measurements
The rest of the whole face set, then the nearest measurements elsewhere on the face. Every one is computed on the same photograph, in the same run, with its own error bar.
Also: how bone-level measurements are taken from a photo · methodology · glossary · all 35 insight pages