Facial Thirds: Measure Your Face Proportions From One Photo

The three sections

Upper third. From the trichion, where the hairline begins at the centre of the forehead, down to the glabella, the smooth area between the brows.

Middle third. From the glabella down to the subnasale, where the base of the nose meets the upper lip.

Lower third. From the subnasale down to the menton, the lowest point of the chin.

Divide each by the total and you get three percentages. The classical convention says each should be close to 33 percent.

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Where the equal-thirds idea comes from

This matters, because the convention is usually presented as though it were a biological finding.

It is not. It comes from artistic canon, specifically the proportional systems taught in Renaissance workshops and codified in figure drawing instruction, with roots in classical Greek sculptural proportion. Leonardo's proportional studies are the most cited source. These were rules for constructing a figure on a page, and they were explicitly idealised. They were never a description of how human faces are actually distributed.

Modern anthropometric measurement finds substantial variation. Equal thirds is uncommon. Most people have a longer lower third or a shorter upper third, and the deviations cluster differently across populations.

So the useful reading of your result is descriptive, not evaluative. Knowing that your lower third is 37 percent tells you something real about your proportions. It does not tell you that 33 would be better.

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What the sections actually correspond to

Upper third is forehead height, which is really hairline position. It is the least stable of the three and the most affected by things that have nothing to do with facial structure.

Middle third covers the eye region and the nose. It is the most stable across adulthood and the least modifiable.

Lower third covers the mouth, jaw, and chin. It is the most functionally significant, the most affected by dental structure, and the section most often addressed clinically.

The lower third also subdivides, and this subdivision is often more informative than the thirds themselves. From the subnasale, roughly the upper third of that section falls to the lip line, and the lower two thirds to the menton. Deviation here relates to lip proportion, chin height, and vertical dental positioning, and it is what maxillofacial and orthodontic assessment actually looks at.

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The hairline problem

This is the main measurement difficulty with facial thirds, and it deserves its own section.

The upper third is measured from the trichion, and the trichion moves. Hairlines mature through the late teens and twenties in most men, and recede beyond that in many. There is no stable anatomical point where a receded hairline used to be.

The consequences:

• On a mature or receding hairline, the measured upper third grows larger without any change to the underlying face
• Where exactly a tool places the trichion on an uneven or receded hairline shifts all three percentages
• Two tools measuring the same photo can differ substantially for this reason alone

What we do: detect hairline recession and, where it is present, lower confidence on the upper third and report a range rather than a single value. The middle and lower thirds are measured against fixed anatomical landmarks and remain reliable regardless.

If your upper third comes back with low confidence, that is why, and the middle and lower figures are still trustworthy.

Practical note: if you have a receded hairline, the lower two thirds and the lower third subdivision are the useful numbers on this page. The upper third is measuring your hairline, not your face.

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Other reasons numbers differ

Head tilt. Any pitch, meaning chin up or down, compresses or extends the apparent sections unevenly. We detect and gate on this.

Brow position. The glabella is a fixed bony landmark, but on photos with heavy brows or shadow the boundary can be placed slightly high or low.

Hair. Hair falling over the forehead obscures the trichion entirely. Push it back for the photo.

Full method: Methodology

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What changes facial thirds

Almost nothing, non-surgically. These are skeletal proportions, set once growth completes.

The lower third is the exception. It is affected by dental structure and vertical jaw position, both of which can change:

• Orthodontic treatment, which alters vertical dental positioning and can change lower third height
• Tooth loss, which reduces lower face height as the supporting bone resorbs
• Orthognathic surgery, which repositions the jaws and is performed for functional bite reasons with proportional effects
• Chin surgery, genioplasty, which alters chin height and projection

The upper third can be changed cosmetically through hairline lowering surgery or hair transplantation, which lower the trichion. This changes the measurement by changing where the hairline is.

Things that do not work: facial exercises, mewing for proportional change in adults, posture work. None of these alter vertical skeletal proportion after growth.

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How to read your result

If your thirds come back close to equal, that is a fact about your proportions and nothing more.

If one section deviates noticeably, the most useful thing to know is that this is common, and that the visual effect is usually smaller than the number suggests. A lower third at 37 percent against a nominal 33 is a four point deviation that most people would never consciously identify.

Where the numbers become genuinely useful is in styling decisions. A tall upper third suggests hair worn forward rather than swept back. A long lower third pairs differently with beard length than a short one. Those are actionable. Chasing 33 percent is not.

Your face shape classification uses related measurements: Face Shape Test

Related: Midface Ratio Calculator · Gonial Angle Calculator · Run the full scan

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FAQ

What are the ideal facial thirds?

The classical convention says three equal sections, but this comes from Renaissance artistic instruction rather than from measurement of real populations. Anthropometric data shows substantial normal variation, and equal thirds is uncommon.

Why is my upper third larger than the others?

Usually the hairline. The upper third is measured from where the hairline begins, so hairline maturation or recession increases that measurement without any change to your facial structure.

Can you change your facial thirds?

The middle third is essentially fixed in adulthood. The lower third can change through orthodontic treatment, tooth loss, or jaw surgery. The upper third changes only through hairline surgery or transplantation.

Does mewing change facial thirds?

There is no good evidence for meaningful vertical skeletal change in adults from tongue posture. Documented proportional changes from orthodontic intervention come from treatment during active growth.

What is the lower third divided into?

From the base of the nose, roughly the upper third of that section falls to the lip line and the lower two thirds to the chin. This subdivision relates to lip proportion and chin height and is often more informative than the main thirds.

How do I measure facial thirds with a receding hairline?

The upper third becomes unreliable, because there is no stable point where the hairline used to be. The middle and lower thirds are measured against fixed landmarks and remain accurate.