Nasal index
How wide the nose is compared with how tall it is: alar width divided by nasal height (sellion to subnasale), × 100.
Also searched as nose width to height, nose shape ratio and broad nose.
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, and a single "ideal" for it 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). 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
- 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
Common questions
What is nasal index?
How wide the nose is compared with how tall it is: alar width divided by nasal height (sellion to subnasale), × 100. Classical anthropometric bands: leptorrhine < 70, mesorrhine 70–84.9, platyrrhine ≥ 85. Population means span roughly 62 to 90.
How is nasal index measured from a photo?
It is computed from the face-mesh landmarks (al_R, al_L, n, sn): 100 × alarWidth / dist(n, sn). Every value carries a 1σ error bar propagated from the landmark detector's published accuracy, with a floor of ± 3, so a small difference inside the interval is not a difference.
What is a normal nasal index?
Reference means and standard deviations from the anthropometric literature, by population. North American White: 62.055 ± 5.4 for women, 63.686 ± 5.96 for men; East Asian: 74.737 ± 7.07 for women, 76.238 ± 6.71 for men; South Asian: 69.792 ± 6.48 for women, 70.874 ± 6.699 for men; African / African diaspora: 82.474 ± 8.051 for women, 84.466 ± 8.178 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 nasal index mean?
Below the mean: the nose is narrow relative to its height for the reference group (toward the leptorrhine band). Above the 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, and a single "ideal" for it is meaningless.
How reliable is nasal index from a photograph?
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.
Nose breadth is on the dimorphism scale, with its effect size and source listed.
Related measurements
The rest of the nose 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