Canthal tilt test
Measure the tilt of each eye from one straight-on photo. Check the four eye-corner points, move any that missed, and read the angle with its limits. Free, and your photo never leaves your browser.
Measured in your browser. Your photo is never uploaded.
How it's measured.
For each eye, Forma draws a line from the inner corner to the outer corner and measures its angle against the line through both inner corners. A positive angle means the outer corner sits above that line.
Many calculators measure against the edge of the photo instead. Then a head tilted by 3° adds 3° to one eye and takes 3° from the other. Using the inner-corner line removes that error, so the two eyes can be compared.
- Take the photo straight on, at eye level. Raising or lowering the chin changes how high the eye corners appear. In one study of 24 eyes photographed from −15° to +15° of head tilt, the measured corner heights changed significantly (Vaca 2022).
- Keep a relaxed, neutral face. Smiling moves the outer eye corners: a 3D study of 41 adults found clear eye-region changes in a posed smile (Xiao 2025).
- Check the points. The face model estimates corners; it was built for AR effects, not clinical measurement. Its published single-photo error is about 3% of the distance between the eyes (MediaPipe Face Mesh V2 model card). By our estimate that can move one eye's angle by about 2°, so treat differences of a degree or two as noise.
What studies report.
No single number is normal. Results depend on who was measured, their age, and which reference line the study used.
- 76 Korean adults, standardized photos at 1.5 m: about +8.5° on both sides, measured against a line perpendicular to the facial midline. No one in the sample had a negative tilt (Lee 2020).
- 296 patients from one US surgeon's photo archive: median lateral canthal angles of about 2.3° (Caucasian) and 3.0° (African American) at 45 or younger, falling to about 1.3° and 1.2° over 45 (Odunze 2008).
- 101 Caucasian and 46 Chinese adults aged 18–30, 3D scans: the Chinese participants' eye axes slanted upward more than the Caucasian participants', with wide variation between individuals (Gao 2025).
Attractiveness. In one study, people preferred digitally exaggerated upward tilt in edited female faces (Bashour & Geist 2007). Another compared seven composite faces and found the "attractive" composites differed by group, with no statistics (Rhee 2012). We found no study linking natural tilt to rated attractiveness in a measured population. That's why Forma reports the angle and never grades it.
Forma's measurement is its own 2D definition; these studies used different lines, photos and samples, so compare with care. Sources checked 2 October 2026.
Questions.
What is canthal tilt?
Canthal tilt is the angle of the line from the inner corner of the eye (medial canthus) to the outer corner (lateral canthus). It is positive when the outer corner sits higher and negative when it sits lower. Studies measure it against different reference lines, so numbers from different sources are not directly comparable.
How does this canthal tilt test measure it?
It finds both corners of each eye with Google's MediaPipe face landmark model, running in your browser. Each eye's angle is measured against the line through your two inner corners, so a tilted head or crooked camera does not change it. You can drag any point that missed its corner and the number updates.
Is a positive canthal tilt more attractive?
The evidence is thin. One study found people preferred digitally exaggerated upward tilt in edited female faces, and another compared seven composite faces without statistics. No study we found measured natural tilt in a population and linked it to rated attractiveness with a reported effect size. Forma does not grade your tilt.
How accurate is a canthal tilt test from a photo?
Not precise enough to split hairs. The face model's published single-photo error is about 3% of the distance between the eyes, which can move one eye's angle by roughly 2°. Head nod and expression also change it. Readings within ±2° of level are reported as about level.
What is a normal canthal tilt?
There is no single normal value. Published averages differ by population, sex, age and method: a Korean sample of 76 adults averaged about +8.4° against a line perpendicular to the facial midline, and median angles in one US clinical archive were about 1–3° and lower in people over 45.
Is my photo uploaded?
No. The photo is decoded and measured in your browser tab and is cleared when you leave or reload. Forma only counts that the tool was used, without any identifier.
Measure the rest the same way.
Width, eye spacing, lower face and side profile, with a photo check and one change to try.
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