Facial thirds: what they are and how to measure yours

What are facial thirds?

Facial thirds divide the front of the face into three horizontal bands. The upper third runs from the hairline to the brow line (the smooth spot between your eyebrows), the middle third from the brow line to the base of the nose, and the lower third from the base of the nose to the bottom of the chin. The classic rule says the three bands are about equal in height.

The lower third has a rule of its own: the upper lip, from the base of the nose to where the lips meet, takes up about one third of it, and the lower lip and chin take up the other two thirds. That 1:2 split comes up a lot when people talk about a “short” or “long” chin.

Thirds describe vertical balance, so they answer a different question from face shape, which compares the face’s length with its width. A face can be any shape and have any mix of thirds.

Where does the equal thirds rule come from?

Equal thirds is one of the so-called neoclassical canons, simple proportion rules that artists used for centuries to draw a believable face. They’re still useful for drawing, and surgeons and orthodontists use the thirds as a rough reference when they plan treatment. They were never measurements of real people, though.

When researchers measure real faces, equal thirds turn out to be rare. Leslie Farkas and colleagues tested the classic canons on young North American adults in 1985 and found the equal-thirds rule in only a small share of them. A 2015 study of young adults from the Arabian Peninsula found no one with three equal thirds, and the lower third was longer than the middle third in about nine in ten people. Those studies used clinical landmarks that don’t sit exactly where a photo tool’s points do, so their numbers and a photo’s aren’t directly comparable.

So treat equal thirds as a midpoint to measure from, not a standard your face has to meet.

How to measure your facial thirds at home

You need one straight-on photo and any app that shows pixel positions or lets you draw lines. Because you’re comparing the thirds with each other, pixels work as well as inches.

Expect the upper third to be the shakiest number. Hairlines are soft-edged, uneven and change with age, and a receding or very low hairline moves the answer a lot without anything else about your face changing. That’s why many people (and FaceRater) compare only the middle and lower thirds.

• Pull your hair back so the hairline shows, or skip the upper third if it’s hidden or has receded.
• Hold the camera at eye height and at least an arm’s length away, with your head level. Tipping your chin up or down shortens one third and stretches another.
• Keep a relaxed face with lips gently closed. Smiling pulls the lower third shorter.
• Mark four points down the center of your face: the hairline, the brow line between your eyebrows, the base of the nose where it meets the upper lip, and the bottom of the chin.
• Measure the three gaps between them in pixels.
• Divide the middle third by the lower third. Around 1.0 means they’re about equal; above 1 means a longer middle third.
• For the lower-third split, mark where your lips meet and divide the upper-lip part by the lips-and-chin part. The classic 1:2 rule is 0.5.
• Take two or three photos the same way and average them. If the numbers jump around, it’s the photos, not your face.

What are normal facial thirds ratios?

FaceRater compares two of these ratios with 2,560 front-facing adult photos from FairFace, a public research set balanced across seven groups. The table shows the middle value, the range the middle half of those faces falls in, and the range that covers eight in ten of them. The middle third here starts at a landmark between the brows, so values may differ a little from a ruler on your own photo.

Two things stand out. The typical middle-to-lower ratio sits close to the classic 1.0, and the typical upper-lip split close to 0.5, so the rules make reasonable midpoints. But the spread around them is wide: a face at 0.89 or 1.12 is still inside the middle eight in ten, and nothing about those faces is “off.”

To read your own number, compare it with the middle half first. Inside that range, your thirds are as typical as they get. A little outside it, your face simply leans longer in the middle or longer below the nose, which is a description of your spacing rather than a flaw. Only values well beyond the eight-in-ten range are genuinely uncommon, and even then a photo taken at a slight angle is the most likely explanation, so retake it before drawing any conclusions.

What does a long midface or short lower third mean?

Mostly, it describes how your features are spaced. A longer middle third puts more distance between the eyes and the mouth; a longer lower third gives more room to the lips and chin. Either can look striking. In FaceRater’s harmony score the thirds count for a quarter of the result, alongside horizontal spacing, the eyes, the jaw and symmetry, so no single ratio decides much on its own.

If your thirds feel unbalanced, styling is where the easy changes are. A fringe or a lower part shortens how tall the forehead reads; crown volume does the opposite. A beard can lengthen or square the lower third, and hair that ends near the chin draws attention to it. Questions about bite, jaw growth or surgery belong with an orthodontist or surgeon, not a photo app.

If you’ve seen “midface ratio” online, that’s a different measurement: it compares the width between your pupils with the height of the middle of your face.

Can an app measure facial thirds?

Partly, and it should tell you which part. FaceRater’s attractiveness test measures the two thirds ratios in the table: brow line to nose base against nose base to chin, and the upper lip against the lower lip and chin. Open the Facial thirds part of your result to see both values next to the common range of the reference faces, with the lines drawn on your photo. That part counts for 25% of your harmony score.

It doesn’t measure the upper third. The landmark model finds a point on the forehead, not the hairline, so any “equal thirds from the hairline” figure from a photo app is a guess at the top. The test also checks your head angle and expression, and flags or refuses photos where a tilted head or a smile would distort the vertical proportions.