Face Shape Detector

Categories are a starting point for styling, not a description of who you are. Two people given the same label can look nothing alike, because the label compresses four numbers and discards skin, expression, coloring, feature size and profile depth.

They also sit on a continuum, and plenty of faces land within a few hundredths of a boundary. What makes the reading repeatable is the set of measurements underneath it.

Measurements come as one vertical and three horizontal, each taken from named skeletal landmarks rather than eyeballed.

• Forehead width spans the broadest part of the brow ridge, roughly halfway between the eyebrows and the hairline.
• Cheekbone width runs between the outermost points of the zygomatic arches, usually the widest chord available.
• Jaw width connects the two gonial angles, where the mandible turns upward toward the ears.
• Face length drops from the hairline midpoint to the base of the chin.

Those four also produce the taper profile, which compares the three widths and reports whether the outline narrows upward, narrows downward, or runs parallel. Taper plus the ratio resolves five categories on its own.

The remaining pair needs the gonial angle. Below roughly 120 degrees the jaw reads square and defined. Above roughly 135 degrees it reads soft and rounded. That angle is the only thing separating a square outline from a round one when their proportions are near identical, which is why both sit together in the comparison below.

Oval is the reference the other six get described against: moderately long, widest at the cheek, curving gradually from temple to chin. Oblong is a square stretched vertically. Heart and triangle mirror each other, one tapering down and one tapering up. Diamond turns up least often, since it needs both the forehead and the mandible narrower than a pronounced cheekbone line. Each label drags styling conventions along with it.

Styling conventions run on one principle: counterbalance. Add apparent width where the outline is narrow, add height where it's short, soften where the line is hard.

• Oval takes nearly anything. Skip heavy full fringes, which cut visible length.
• Round wants lift at the crown, volume kept off the sides, long layers and angular rectangular frames.
• Square softens under textured wispy layers at the jaw, plus curved or oval frames.
• Oblong gains from horizontal interest: a blunt fringe, cheek-level waves, deeper frames.
• Heart balances a broad forehead with fullness lower down: a chin-length bob, bottom-heavy or rimless frames.
• Diamond opens up through a side-swept fringe and cuts that fill the narrow lower third.
• Triangle pulls the proportions upward with volume above the ears and lighter weight along the mandible.

None of it survives a bad photograph, which is where most disputed results begin.

Photographs decide the numbers, so five capture conditions matter more than the algorithm does, listed here in descending order of impact.

1. Clear the hair off the face entirely. Anything crossing a temple or a jaw corner drags the detected outline inward, enough to move you a whole category.
2. Hold a neutral expression, mouth closed. Smiling recruits the zygomatic muscles and inflates apparent cheekbone width.
3. Put the lens at eye level, about an arm's length away. Low angles fatten the jaw; high angles fatten the forehead.
4. Light the face evenly from the front. Side light sinks one cheek into shadow, and the mesh then follows the shadow edge instead of the bone.
5. Avoid wide-angle selfie distortion. Short focal-length front cameras enlarge whatever sits nearest the sensor. Step back and crop in.

Keep your head level and square to the lens. Ten degrees of yaw compresses one side and shifts every horizontal reading, and projection sets the ceiling on accuracy.

Accuracy is capped by the medium. A photograph is a flat projection of a three-dimensional skull, so depth gets inferred rather than measured. How far a cheekbone comes forward, how deep a chin sits: neither is in the picture, and two people with different profiles can share one frontal outline.

Borderline readings are common and are not errors. A ratio of 1.47 sits on the oval-to-heart boundary, and a small change in lighting or pose tips it either way. Two labels from two photos means you carry features of both.

Reported reliably: your proportions, which region is broadest, which is narrowest, and how the thresholds relate to those figures. Not reported at all: health, ancestry, character or attractiveness. The numbers are objective. The aesthetic conclusions drawn from them are conventions, and any convention you dislike can be ignored.

Seven categories, four measurements, one browser tab. The system compresses a head outline into three horizontal chords, one vertical drop, a taper profile and a gonial angle, then names the closest of oval, round, square, heart, diamond, oblong or triangle. The table shows how each differs from its neighbors, the styling section converts a label into haircut, fringe and eyewear choices, and the capture checklist protects the numbers from hair, expression, camera height and lens distortion. The limits stay on the page: flat projection, soft boundaries, nothing medical. Upload a level frontal shot to the face shape detector and read the ratios, not just the name at the top.