Nasal index
Alar width divided by nasal height (sellion to subnasale), × 100.
How to read it
the nose is narrow relative to its height for the reference group (toward the leptorrhine band).
nasal index sits close to the reference mean.
the nose is wide relative to its height for the reference group (toward the platyrrhine band). Reference means differ by nearly 30 index points across populations — this is among the most population-specific of all facial proportions, which is exactly why a single "ideal" is meaningless.
Nasal height is a vertical measure and is foreshortened by pitch; alar width is inflated at short camera distance. Both errors push the index the same direction, so read it with the capture panel.
Reference values by population
| Reference population | Female (mean ± SD) | Male (mean ± SD) | n | Source |
|---|---|---|---|---|
| North American White | 62.055 ± 5.4 | 63.686 ± 5.96 | 2326 | Farkas 1994/2005 (NA White young adults) prov. |
| East Asian | 74.737 ± 7.07 | 76.238 ± 6.71 | 618 | Farkas 2005 (Chinese/Japanese/Vietnamese/Thai pooled); Jayaratne 2012 (Southern Chinese, n=103) prov. |
| South Asian | 69.792 ± 6.48 | 70.874 ± 6.699 | 210 | Farkas 2005 (Indian); Metgudmath 2022 prov. |
| African / African diaspora | 82.474 ± 8.051 | 84.466 ± 8.178 | 300 | Farkas 2005 (African-American, Zulu, Angolan) prov. |
| Middle Eastern | 63.725 ± 5.798 | 64.545 ± 5.972 | 348 | Farkas 2005 (Turkish, Iranian, Egyptian); Al-Sebaei 2015 (Saudi, n=168) prov. |
| Hispanic / Latino | 70.833 ± 6.678 | 71.845 ± 6.886 | 120 | Farkas 2005 (Mexican-American) prov. |
| Not specified — show pooled | 70.468 ± 8.884 | 71.755 ± 8.976 | 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). For a typical 300 px inter-pupil photo that is ≈12 px per landmark, which is why small ratios and angles get wide intervals. A number without an interval is a number pretending to be more precise than it is.
References
- Nasal index classification (Martin & Saller; as used by Farkas 2005): leptorrhine < 70, mesorrhine 70–84.9, platyrrhine ≥ 85. doi.org/10.1097/01.SCS.0000171847.58031.9E
- 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
- Ward, Ward, Fried & Paskhover (2018). Nasal Distortion in Short-Distance Photographs: The Selfie Effect. JAMA Facial Plast Surg. doi.org/10.1001/jamafacial.2018.0009
Related: how bone-level measurements are taken from a photo · methodology · all insights