Free tool · runs in your browser
Canthal Tilt Calculator
Measure the angle between your inner and outer eye corners from a front-facing photo. See each eye in degrees, understand positive, neutral and negative tilt, and check both sides before reading the average.
Drop a photo, paste one, or choose a file
Straight-on, whole face visible, even light. JPG, PNG or WebP.
Runs in your browser. Your photo never leaves your device.
Positive, neutral or negative?
Follow the corners, not the eyebrow.
Canthal tilt describes the line between the inner and outer corners of the eye relative to a horizontal reference. These schematic examples show one eye from inner corner to outer corner; they are not beauty scores.
Positive canthal tilt
Neutral canthal tilt
Negative canthal tilt
Blue: corner-to-corner line. Dashed gold: horizontal reference. Symmi labels values ≥ +2° positive and ≤ −2° negative, with a neutral interval between them. These display cutoffs are not medical or attractiveness thresholds.
Read each eye before the average.
For example, +5° on one side and −3° on the other average to +1°. A neutral average can hide different directions. Your result lists both eyes and their absolute difference.
Keep the photo setup consistent.
Look straight at an eye-level camera, keep both corners visible and avoid squinting. Use even light and a consistent distance. The tool corrects sideways head roll; it cannot undo a turned face, looking up or down, or perspective.
The corner-to-corner definition is described in this published measurement study. Symmi estimates its reference using the line between pupil centres, so its readings are not interchangeable with every clinical method.
How it is measured
Inner corner to outer corner, after the head is levelled.
Canthal tilt is the angle from the inner eye corner to the outer corner relative to a horizontal reference. A raised outer corner gives a positive angle. Symmi estimates these corners using facial landmarks and levels the line between the pupil centres before measuring. This corrects sideways head roll, but not perspective or a face turned away from the camera.
- Positive
- +2° and above on Symmi's display scale. The outer corner is higher than the inner corner.
- Neutral
- Greater than −2° and less than +2°. A display interval for near-level corners.
- Negative
- −2° and below on Symmi's display scale. The outer corner is lower than the inner corner.
- Left vs right
- Each eye is listed separately, followed by the absolute difference. An average can hide opposite directions. No clinical symmetry cutoff is assigned.
Measure it yourself
How to measure canthal tilt yourself
All you need is a straight-on photo and a way to read positions: a photo editor, or a printed photo and a protractor.
- 1Take a straight-on photo at eye level with a relaxed face and your head not tilted to either side.
- 2Find the inner corner of one eye (where the lids meet, by the nose) and the outer corner.
- 3Draw a reference line through the centres of both pupils. Measuring against this line cancels out a slightly tilted head.
- 4Measure the angle between the corner-to-corner line and the reference. From pixels: angle = arctan(height difference ÷ horizontal distance). An outer corner 2 px higher over 40 px is arctan(2/40) ≈ 2.9°.
- 5Repeat for the other eye. The two eyes often differ by a degree or two.
Skip the ruler: the free tool above does it from one photo in about 30 seconds ↑
What's normal
Positive, neutral and negative tilt
These are Symmi's display cutoffs. They describe direction, not health or attractiveness, and studies that use other landmarks report numbers that aren't directly comparable.
- +2° and above
- Label: Positive
- What it means: The outer corner sits higher than the inner corner.
- Between −2° and +2°
- Label: Neutral
- What it means: The corners are close to level.
- −2° and below
- Label: Negative
- What it means: The outer corner sits lower than the inner corner.
Sources
What this is based on.
The measurement and its reference ranges come from published research. Studies use different methods and populations, so compare your number with the range shown on this page rather than with other tools.
- 1.
Lee JY, Choung HW, Choung PH (2020). Diagnostic analysis of vertical orbital dystopia and canthal tilt for surgical correction. Journal of the Korean Association of Oral and Maxillofacial Surgeons. PubMed 33377462
Defines the canthal tilt angle measured from the inner to the outer eye corner.
- 2.
Rhee SC, Woo KS, Kwon B (2012). Biometric study of eyelid shape and dimensions of different races with references to beauty. Aesthetic Plastic Surgery. PubMed 22810555
Eyelid shape and canthal measurements compared across ethnic groups; normal values differ by population.
- 3.
Kartynnik Y, Ablavatski A, Grishchenko I, Grundmann M (2019). Real-time facial surface geometry from monocular video on mobile GPUs. arXiv. arXiv:1907.06724
The face-mesh model that places the 468 surface landmarks this tool measures from.
- 4.
Ablavatski A, Vakunov A, Grishchenko I, et al. (2020). Real-time pupil tracking from monocular video for digital puppetry. arXiv. arXiv:2006.11341
The iris model that adds 10 eye landmarks (478 in total), used for pupil-based reference lines.
Our own data: how much each reading moves when the same face is photographed again is published on the methodology page. How we choose sources.
Related tools
Eye Shape Guide & Self-check
Compare crease, outline and direction separately.
Eye Spacing Test
Inner-corner gap relative to average eye width.
Hunter Eyes vs Prey Eyes
What separates the two, side by side.
Face Symmetry Test
Eye height and eye width, left vs right.
Facial Thirds Test
Where the eyes sit in the face's vertical thirds.
FAQ
What is positive or negative canthal tilt?+
Positive means the outer eye corner is higher than the inner corner relative to the measurement reference; negative means it is lower. Symmi uses +2° and −2° as display cutoffs, with a neutral interval between them. These are not medical or attractiveness thresholds.
What is a good canthal tilt?+
There is no universal target in this tool. A positive or negative label describes direction, not health, attractiveness or a need to change your eyes. Read the measured angle alongside the photo and its limitations.
Why is my result different from another calculator?+
The selected corner points, horizontal reference, photo pose and landmark estimates may differ. Some methods use a facial midline or a different anatomical reference. There is no fixed conversion or correction in degrees that makes every method equivalent.
Can the result change between photos?+
Yes. Squinting, expression, lighting, camera angle and landmark placement can change a photo estimate. This tool cannot establish whether your anatomy changed or whether a routine changed it. Use comparable photos when checking repeat measurements.
Does head tilt affect it?+
Yes. The tool estimates sideways head roll from the pupil centres and corrects it before measuring. That reference is itself an estimate; correction cannot undo looking up or down, turning to one side or perspective distortion.
Is this the same as eye shape?+
No. Canthal tilt describes corner direction. Eyelid contour, how open the eye appears and the upper-lid fold are different features. One tilt angle cannot classify the whole eye shape.
Is my photo uploaded?+
No. Landmark detection and angle calculations run in your browser.
One reading here.
Nineteen in the app.
A controlled scan, every reading against its ideal band, bone vs trainable, a plan, and a 3D model on Face ID iPhones.