Facial thirds: how the face divides
Facial thirds split the face vertically into three parts: hairline to brows, brows to the base of the nose, and the base of the nose to the bottom of the chin. Equal thirds are a drawing convention, not a target, and most faces differ a little. The ratio describes proportion, and it shifts with camera height, head pitch and where the lines are placed.
What the facial thirds are
The facial thirds come from portrait drawing, where artists lay out a face by dividing its height into three bands of roughly equal size. The same idea is used in anthropometry, photography and hair styling as a quick way to describe vertical proportion: how the forehead, the mid-face and the lower face compare with each other.
- Upper third: from the hairline at the center of the forehead down to the brow line.
- Middle third: from the brow line down to the base of the nose, where it meets the upper lip.
- Lower third: from the base of the nose down to the lowest point of the chin.
In anatomical terms the four boundary points are often given as the trichion (hairline), the glabella or nasion (between the brows), the subnasale (base of the nose) and the menton (bottom of the chin). Sources differ on which brow point to use, which is the first reason two measurements of the same face can disagree. The glossary defines these and related terms such as facial fifths.
Where each third starts and ends
| Third | From | To | What shifts it in a photo |
|---|---|---|---|
| Upper | Hairline | Brow line | Hairline shape, a fringe, forehead slope, camera above eye level |
| Middle | Brow line | Base of the nose | Head tipped up or down, raised brows, lens distance |
| Lower | Base of the nose | Bottom of the chin | Mouth open or closed, jaw clenched, beard, chin tucked |
The upper third is the least stable of the three because the hairline is not a fixed anatomical point. It can be curved, uneven or receding, and a fringe hides it entirely. Some measurements therefore compare only the middle and lower thirds, which both have clearer landmarks.
How to measure your facial thirds from a photo
- Set up a straight-on photo. Camera at eye level and an arm’s length or more away, head level, lips closed with teeth lightly together, hair held off the forehead.
- Draw four horizontal lines. One where hair growth starts at the center of the forehead, one across the brows (choose the lowest point between them or the brow centers, and stick with that choice), one where the nose meets the upper lip, and one at the lowest point of the chin.
- Measure the three gaps. Measure each gap in pixels along the vertical center of the face rather than at an angle.
- Turn the gaps into shares. Add the three gaps together and divide each one by the total to get the share of face height each third takes up.
- Repeat and average. Measure a second photo taken the same way. Differences between the two are measurement noise, so the average is a fairer reading than either one.
The hairstyle guide shows how these proportions feed into choosing a cut, and the free face shape tool gives a quick in-browser reading of overall proportions.
Reading the facial thirds ratio
There are two common ways to write the ratio. The first gives each third as a share of total face height. As an example of the arithmetic only, gaps of 58, 62 and 65 pixels add up to 185, so the thirds take up about 31, 34 and 35 percent. The second compares each third with the middle third, which would give roughly 0.94 : 1 : 1.05 for the same numbers.
Neither form comes with a correct answer. A longer lower third or a shorter upper third is a description of proportion, and online communities often regard balanced thirds as desirable; there is no single correct value, and the measurement is very sensitive to head tilt, camera height and expression. Some conventions split the lower third again at the mouth, comparing the upper lip with the lip-to-chin distance, which adds two more points that move with expression.
Thirds are a fixed trait, set mostly by the skeleton. They are a finding about your face, not something to change. What a hairstyle, a fringe or a beard changes is how the upper and lower thirds read, not their measured length.
Why two measurements rarely agree
- Camera height. A camera above eye level makes the forehead look larger and the chin smaller; below eye level does the opposite.
- Head pitch. Tipping the chin up or down compresses one end of the face and stretches the other, because the face is curved, not flat.
- Lens distance. A close, wide-angle selfie enlarges the nose and mid-face relative to the forehead and chin.
- Line choices. Hairline, brow point and chin point all involve judgment, and moving any of them changes two thirds at once.
- Expression and facial hair. An open mouth lengthens the lower third, and a beard hides where the chin actually ends.
How MaxxLook approximates the thirds
MaxxLook’s thirds reading is an approximation built from the 478-point face mesh on your front photo, one of 170+ measurements in a scan. It splits the face at four cut points, the top of the mesh, the center of the brow region, the center of the nose region and the center of the chin region, and scores how balanced the three resulting parts are. It does not use the hairline, the nasion, the subnasale or the menton.
| Boundary | Traditional landmark | MaxxLook cut point |
|---|---|---|
| Top | Hairline (trichion) | Top of the face mesh, which sits below the hairline |
| Upper to middle | Between the brows (glabella or nasion) | Center of the brow region |
| Middle to lower | Base of the nose (subnasale) | Center of the nose region |
| Bottom | Lowest point of the chin (menton) | Center of the chin region |
Because the mesh top sits below the hairline and the other cut points are region centers, MaxxLook’s numbers will not match a ruler on a photo, and they are not meant to. The upside is consistency: hair and a receding or hidden hairline do not move the reading. Like other proportion readings, it is compared with reference ranges built by running the same pipeline over the FairFace image collection, explained on the transparency page. Profile and quarter photos feed no geometry, so the thirds come from the front photo alone.
Common questions
Should all three facial thirds be equal?
No. Equal thirds are a drawing convention, and most faces differ a little between the upper, middle and lower third. Online communities often regard balanced thirds as desirable; there is no single correct value, and the measurement is very sensitive to head tilt, camera height and expression.
Why does my upper facial third measure differently in every photo?
The upper third runs from the hairline, which is not a fixed anatomical point, to the brows, which move with expression. A fringe, a curved or receding hairline and a camera above eye level all change it, so many measurements compare only the middle and lower thirds.
Why doesn’t MaxxLook’s thirds reading match a ruler on my photo?
MaxxLook splits the front-photo face mesh at its top, the brow-region center, the nose-region center and the chin-region center rather than at the hairline, nose base and chin tip. The mesh top sits below the hairline, so its upper third is shorter by design.