Face Symmetry Test From a Photo

The tool uses the same in-browser face model as the rest of the detector to place 68 landmark points: around the jaw, along each eyebrow, around each eye, down the nose and around the lips. Before comparing anything it levels the face using the line between the eyes, so a slightly tilted head does not count as asymmetry. It then fits a vertical midline through the bridge of the nose and the chin.

Each landmark on one side has a partner on the other: the outer corner of the left eye and the outer corner of the right eye, the two mouth corners, matching points on the jaw. The tool mirrors one side across the midline and measures how far each point lands from its partner, scaled to the size of the face so a close-up and a distant shot are comparable. Small distances mean the two sides line up closely; larger ones mean they differ.

The symmetry index rolls all the pairs into one number from 0 to 100, where higher means the mirrored points lined up more closely in this photo. The region scores split that up, so you can see that the eyes and nose may match closely while the mouth or jaw accounts for most of the difference. That breakdown is usually more interesting than the headline number.

The overlay shows the midline and the landmark pairs on the photo, which lets you check the measurement yourself. If a point has landed on a shadow or a strand of hair rather than the feature, the score for that region is measuring the wrong thing, and a cleaner photo will give a fairer result.

• Eyes: height and width of each eye relative to the midline.
• Brows: the arch and height of each eyebrow.
• Nose: how centred the nose tip and nostrils sit on the midline.
• Mouth: the height and spread of the two mouth corners.
• Jaw: the outline of the jaw and chin on each side.

Mirror faces splits the photo along the midline and builds two composites: one made of your left half and its mirror image, and one made of your right half and its mirror image. The two often look surprisingly unlike each other, and unlike you, which is a vivid way to see how much everyday asymmetry a face has. The composites are drawn in your browser and are not saved anywhere.

Natural asymmetry is normal. Bone growth, teeth, which side you sleep on, old injuries and simply habit all leave the two halves of a face slightly different. Expressions are asymmetric too: most people smile, frown or raise an eyebrow more on one side. A perfect 100 would be very unusual, and a modest score does not mean anything is wrong.

The photo adds its own asymmetry on top. Turning the head even a few degrees makes the near side look wider. A phone held close to the face exaggerates whatever is nearest the lens. Light from one side darkens one half and can pull landmark points off their features. That is why the same face can score differently in two photos taken a minute apart.

• Face the camera straight on, with your nose pointing at the lens.
• Keep a relaxed, neutral expression; smiles and raised brows are rarely even.
• Hold the camera at arm's length or further to avoid close-up lens distortion.
• Use soft, even light from the front rather than a window to one side.
• Move hair, glasses and hats away from the brows, eyes and jaw.
• Compare two or three photos and look at what stays the same.

Plenty of sites turn face symmetry into an attractiveness rating. This one does not. Research on symmetry and attractiveness is mixed, the effects people point to are small and vary between studies, and a number from one photo measures the photo as much as the face. Treat the index as a curiosity and a way to compare your own photos, not as a verdict on anyone's looks.

If you want to look at proportions rather than left-right balance, the golden ratio face page uses the same landmarks to measure the mouth-to-nose ratio, face width against brow-to-chin length and the facial thirds, with the same caveats.