Facial symmetry has been studied extensively as a marker of biological fitness and developmental stability. Research shows that more symmetrical faces are often rated as more attractive across cultures — but the effect size is modest, and many other factors play a larger role.
Importantly, no human face is perfectly symmetrical. The left and right sides of every face develop slightly differently. A symmetry score of 100 would be unusual and even unsettling — slight asymmetry contributes to the distinctiveness that makes faces memorable and interesting.
8 bilateral pairs: eye positioning, eye width, eyebrow height, nostril width, mouth corner placement, cheekbone position, jawline balance, and temple width.
Most people score between 65–80. Scores above 85 are genuinely uncommon. A score of 70 puts you near the center of the population.