What is chin to philtrum?

The philtrum is the vertical groove and surrounding skin between the base of the nose and the peak of the upper lip. The chin segment runs from the lower lip to the lowest point of the chin. Their relative lengths describe how the lower third of the face is divided.

How Facemap measures chin to philtrum

Facemap places landmarks at the subnasale, the upper lip peak, the lower lip base and the chin point (menton), then measures the vertical distance for each segment along the facial midline. The two lengths are expressed as a ratio.

What the typical range looks like

A commonly referenced target is a philtrum to chin ratio near 1:2, though considerable natural variation exists across bone structure and lip fullness. The reading is descriptive, not a target to chase, and works best alongside the wider facial thirds breakdown.

How to read your result

A ratio close to 1:2 reads as a balanced lower third. A shorter chin segment relative to the philtrum often shows as a softer lower face profile, while a longer chin segment tends to read as more defined. Neither pattern is unusual, and both are common in well-balanced faces.

The chin to philtrum formula: how we calculate it

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

|y(152) - y(17)| / |y(0) - y(2)|

Landmarks used

152, 17, 0, 2

Reference target

2.20

Tolerance band

0.85

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: lower-face vertical balance norms. 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.

Chin to philtrum reference table

Chin to philtrum ratio bands and how each one reads.

• Near 1:2.2Elongated chin

  Chin segment reads notably longer than philtrum

• 1:1.9 to 1:2.1Balanced

  Close to the commonly cited target proportion

• 1:1.6 to 1:1.8Compact chin

  Shorter chin segment relative to philtrum

• Below 1:1.6Short lower third

  Chin and philtrum sit close in length

Why the lower third splits into two segments

Classical facial-thirds analysis treats the lower third as one block, but the philtrum and chin move independently with growth, lip fullness and jaw structure, so a single lower-third measurement can hide two very different segment lengths.

• /Philtrum length is set largely by upper lip and nasal base structure
• /Chin height reflects mandibular growth and soft-tissue coverage
• /The two segments can trend in opposite directions on the same face
• /Comparing them separately gives a clearer picture than a single lower-third score

What influences your chin to philtrum ratio

Several structural factors shape this ratio, and most sit outside anything changeable by expression or posture.

• /Underlying mandibular and chin bone projection
• /Upper lip thickness and vertical lip position
• /Vertical growth pattern of the midface and lower face
• /Natural variation across ethnic and familial facial structure

Getting a reliable philtrum and chin reading

Because both segments are short, small measurement errors shift the ratio noticeably. Face the camera directly with your mouth relaxed and closed, avoid tilting your chin up or down, and keep even lighting across the lower face so the lip and chin landmarks are placed consistently between scans.

The chin to philtrum formula, step by step

The chin to philtrum ratio comes from a simple formula: chin height divided by philtrum length. Facemap's AI face scan places the landmarks and does the division automatically, but the arithmetic behind the calculator is straightforward.

• /Find the subnasale, the point where the base of the nose meets the upper lip
• /Find the upper lip peak to mark the bottom of the philtrum segment
• /Measure the vertical philtrum length between those two points
• /Find the lower lip base and the chin point, or menton, to mark the chin segment
• /Measure the vertical chin height between those two points
• /Divide chin height by philtrum length to get the ratio, commonly close to 2:1