What is nasal index?

A ratio of nasal width, the distance between the outer alar points at the widest part of the nose, to nasal height, the vertical distance from the nasion at the bridge to the subnasale at the base.

How Facemap measures nasal index

Facemap locates the alar points, nasion and subnasale from the 478-point mesh, calculates nasal width divided by nasal height as a percentage, and separately reports nasal width against total bizygomatic face width.

What the typical range looks like

Nasal index varies meaningfully and consistently across ancestry, so there is no single universal reference range. Facemap reports the measured value and its relationship to face width rather than scoring it against one fixed reference point.

How to read your result

Read nasal index alongside your face width, since the same nose width can read as narrow or wide depending on the overall face it sits within. Facemap therefore always pairs the ratio with the nose-to-face width figure.

The nasal index formula: how we calculate it

Nose width against nose height. Landmark numbers are MediaPipe Face Landmarker indices, and every distance is normalised to your own face so camera distance and image size cancel out.

dist(129, 358) / dist(168, 2)

Landmarks used

129, 358, 168, 2

Reference target

0.75

Tolerance band

0.20

Your reading is compared with that published reference on a Gaussian match curve: score = round( 100 x exp( -0.5 x ( (reading - target) / tolerance )^2 ) ), clamped to 1 to 99. Basis for the reference value: classical anthropometric nasal index bands. The headline Attractiveness Score works differently: all readings are corrected for head angle and expression, weighted by confidence and mapped onto a 1 to 100 scale by a model calibrated against a published research set of more than Facemap scans.

Read the full Facemap methodology, including how the 22 measurement categories combine into your Attractiveness Score.

Nasal index reference table

Nasal index bands and how each reads.

• Below 70Leptorrhine

  Narrower nose relative to its height

• 70 to 84Mesorrhine

  The most commonly measured band

• 85 to 99Platyrrhine

  Wider nose relative to its height

• 100 and aboveHyperplatyrrhine

  Notably wide relative to height

How the nasal index is calculated

The ratio uses two measurements taken along and across the nose from a straight-on scan.

• /Nasal width: outer left alar point to outer right alar point
• /Nasal height: nasion at the bridge to subnasale at the base
• /Nasal index equals nasal width divided by nasal height, times 100

Why nasal index varies by ancestry

Nasal index is one of the most studied anthropometric ratios precisely because it varies consistently and meaningfully across population groups, reflecting adaptation and inherited structure rather than any single reference proportion. Comparing your result against a single universal benchmark is therefore not meaningful, which is why Facemap reports the measured value on its own terms.

Nose width relative to face width

A nose can carry a typical nasal index while still reading as proportionally wide or narrow within a particular face, depending on overall face width. Facemap reports nose width as a percentage of bizygomatic face width alongside the classical index so both signals are visible together.

The nasal index formula, step by step

The formula is a straightforward division scaled to a whole number, which is why it has stayed the standard reference in anthropometry for over a century.

• /Measure nasal width: outer left alar point to outer right alar point
• /Measure nasal height: nasion at the bridge to subnasale at the base
• /Divide nasal width by nasal height
• /Multiply the result by 100 to get the nasal index