Three sections
Hairline to brow, brow to nose base, and nose base to chin, taken along the vertical face axis.
Local proportion tool
Facial Thirds Calculator
The classical convention divides the face into three equal vertical sections. This calculator measures yours, reports each as a percentage and shows exactly how far each one sits from 33.3%.
Analyze a photo locally →On-device analysis
Measure your facial thirds
Hairline, brow, nose base and chin landmarks are measured locally to build the three sections.
Photo stays in this browser
Choose one clear adult portrait
Front-facing, neutral expression, even light. JPG, PNG, WebP, HEIC or HEIF up to 10 MB.
or drag and drop it here
Before you analyze
- 1Use your own photo, or one you have permission to use.
- 2One adult face only. No minors or age estimation.
- 3Results describe this photo, not objective beauty or health.
A typical first run loads about 15 MB of model/runtime files, then the browser caches them. Nothing is submitted to our analysis API.
Loading local face model…
The first run can take a moment. Your photo remains on this device.
We could not analyze this photo
Local mode: the selected image and detected landmarks are held in page memory only and are cleared when you reset or leave.
What it measures
Evidence behind this result
The output is built from inspectable photo geometry and a separate image-quality signal.
Deviation per third
Each section is shown with its signed difference from the 33.3% convention.
Balance score
Average deviation is converted into a single 0–100 thirds-balance value.
01Visible landmarks
02Normalized geometry
03Explainable output
Three-step method
How this tool works
Divide
Four landmarks define the three vertical sections on the eye-line-aligned axis.
Normalise
Sections are expressed as percentages of total measured height, so image size does not matter.
Compare
Each percentage is compared with the even-thirds reference.
478 visible landmarksMediaPipe Tasks Vision 0.10.35Model: float16 v1Runs in browser
Read the shared methodology →Interpret carefully
What the result cannot tell you
01
The upper third depends on a visible hairline; receding, covered or shaved hairlines make it the least reliable section.
02
Equal thirds is an artistic drawing convention from Renaissance proportion studies, not a biological norm.
03
Head tilt toward or away from the camera compresses the sections unevenly.
What are the facial thirds?+
A classical drawing convention that divides the face into three vertical sections — hairline to brow, brow to the base of the nose, and the base of the nose to the chin — which the convention treats as roughly equal.
Are unequal thirds a problem?+
No. Most measured faces have unequal thirds. The convention is a compositional guide from art instruction, not a medical or aesthetic requirement.
Why is my upper third unreliable?+
It is bounded by the hairline, which the landmark model estimates rather than measures directly. Hair covering the forehead, or a high or receding hairline, shifts it the most.
Keep exploring
View all tools →Related tools
Facial Harmony Calculator
Get a facial harmony score built from six weighted visible relationships, with what helps it, what reduces it and what is only photo-related.
Open tool →
Facial Ratios Calculator
Measure visible facial thirds, fifth-related spacing and selected width relationships with an exportable annotated image.
Open tool →
Midface Ratio Calculator
Measure your midface ratio — eye-line to upper-lip height divided by interpupillary distance — with the exact definition and pixel values shown.
Open tool →