The calculator maps reference points across your face from a single front-facing photo and measures the width-to-length ratio of your face. Studies on facial proportions put the average ideal around 0.72: a face slightly longer than it is wide. It also checks how your face divides into thirds (hairline to brow, brow to nose base, nose base to chin) and how evenly your features sit left to right.
The analysis runs entirely in your browser. Your photo never leaves your device and nothing is stored.
No real face hits these numbers exactly, and chasing them misses the point. The value is practical: your ratios tell you which direction to push with a haircut. A wider face gains from height on top and tighter sides. A longer face benefits from fringe coverage and side volume. Uneven thirds tell you where a cut should add or remove visual weight. Barbers make these calls by eye; the calculator just shows you the numbers behind them.
For the haircut side of the equation, find your shape with the face shape detector and read the barbering science guide to see how proportions drive cut choices.