Face shapes, measured rather than guessed

A face-shape label here is the nearest of six geometric prototypes. It is not a diagnosis, a temperament, or a ranking of faces. The browser finds a face with MediaPipe, reads a short set of landmark distances, and asks which stored pattern sits closest. The six names are oval, round, square, heart, oblong, and diamond. You can run the measurement on the analyzer. If you consent, the downscaled photo and these ratios are stored, which is the process described in How the analyzer works.

The useful part of the label is line. A neckline, a frame, a collar, a beard edge, and a haircut are drawings placed next to the drawing of the face. Some drawings repeat a line you already have. Some add the line you have less of. That is the styling claim. It does not say who is suited to any role, mood, or story that magazines once attached to these names. The same lines apply whether you wear a beard, a collar, both, or neither.

What the length actually is

Face length is the distance from an upper-forehead point on the face mesh to the chin. In the MediaPipe face landmarker that point is landmark 10, and the chin is landmark 152. Landmark 10 sits on the forehead of the mesh. It is not the place where hair starts. A tailor, a stylist with a tape, and most magazine diagrams start at the hairline, which is higher, and which moves when the haircut changes. Those two lengths answer different questions. Bangs can leave every ratio on this page unchanged, because the measurement never went looking for hair.

The mesh starts lower than a hairline, so the length-to-width numbers run smaller than the figures printed beside shopping-guide diagrams. The oval prototype uses a length about 1.42 times the cheek width. A chart that says an oval is one and a half times as long as it is wide, hairline to chin, is measuring a taller span. Holding the two systems side by side and expecting the same decimals makes a correct mesh reading look wrong. Read the shape pages with that scale in mind: oval, round, square, heart, oblong, and diamond.

The six ratios

Cheek width is the reference for most of the set. It is the distance between the side-of-face landmarks 234 and 454. The other widths are ratios against that span, or comparisons of two widths, plus one angle.

Length to width divides the forehead-point-to-chin distance by cheek width. Jaw to cheek divides jaw width, landmarks 172 to 397, by cheek width. Forehead to jaw divides forehead width, landmarks 54 to 284, by jaw width. Cheek to forehead divides cheek width by forehead width. Chin to cheek divides a short width low on the chin, landmarks 176 to 400, by cheek width. The chin angle is the angle at landmark 152 between those two jaw corners. A larger angle is a more open, less pointed chin. A smaller angle is sharper. A wide jaw and a wide chin angle are different facts, and the round and square prototypes separate them on purpose.

Those six numbers are the whole face-shape input. Eye color, a smile line, and a preferred jacket have no vote. The ratios are computed the same way for any gender. A beard is not a seventh measurement. A heavy beard can hide the jaw the mesh is trying to place, which makes the numbers less stable. A beard is also a line you can shape. Those are separate facts, and only the second one is a styling choice.

How the nearest prototype is chosen

Each shape is a reference vector, using the same landmarks, not a hairline tape.

Oval sits near length 1.42, jaw 0.84 of the cheeks, forehead almost equal to the jaw at 1.03, cheeks a little wider than the forehead at 1.08, chin 0.42 of the cheeks, and a chin angle around 130 degrees. Round is shorter, length 1.18, with a fuller jaw at 0.94, a wider chin at 0.55, and an open chin angle around 148 degrees. Square is also relatively short, length 1.22, but the jaw is nearly as wide as the cheeks at 0.98 and the chin angle is sharper, around 112 degrees. Heart keeps a moderate length at 1.36, with a narrow jaw at 0.72, a forehead much wider than that jaw at 1.28, and a sharp chin angle around 104 degrees. Oblong is the long vector, length 1.68, with jaw and forehead relations close to oval. Diamond is the pattern in which the cheeks outrun the forehead, cheek to forehead about 1.22, while the jaw stays narrow at 0.74.

The classifier does not run a checklist with vetoes. It measures a scaled distance from your six numbers to each prototype. Length is scaled by 0.16, jaw to cheek by 0.08, forehead to jaw by 0.10, cheek to forehead by 0.08, chin to cheek by 0.08, and the chin angle by 14 degrees. Each gap is divided by its scale, squared, summed, and square-rooted. The smallest distance wins. A score is stored as one divided by one plus that distance, so a perfect hit sits near 1 and a far prototype sits lower.

A two-degree change in the chin angle is a small step on that scale. A twenty-degree change is not. No single ratio is allowed to erase the other five, which is why a pointed chin alone does not force a heart label, and a long impression in the mirror does not force oblong if the rest of the vector disagrees.

When two shapes are close

If the best score and the second score differ by less than 0.06, the reading says the face is close between two patterns, and that the named shape is only the nearest. That sentence is the honest output. It is not a failed photo, and it is not an invitation to pick the name you like better from a list of stories. Wear the advice from the nearest label, then borrow the one idea from the neighbor that addresses the ratio you actually share.

Consider a length of 1.30. Oval’s prototype is 1.42 and round’s is 1.18, so the length gap to each is 0.12. Divided by the length scale of 0.16, both gaps are 0.75 before they are squared. Length alone ties them. The jaw ratio, the chin angle, and the forehead then break the tie. A face at that length with a jaw near 0.90 of the cheeks and a chin angle near 128 degrees will not land in a crisp bin. It may sit between oval and round, or between oval and square, depending on the remaining numbers. In that case a deep V and a curved frame can both be tried. You are not required to dress as if you fully occupy a category you only half match. The glasses guide and the neckline guide are written so you can test one line at a time.

Round against square

Round and square both read as wide in a mirror. The split is the chin angle and how close the jaw comes to the cheek width. Round’s prototype angle is about 148 degrees, an open curve, with the jaw a bit inside the cheeks at 0.94. Square’s angle is about 112 degrees, with the jaw almost matching the cheeks at 0.98. A soft photo, a smile, or a beard grown into a curve can make a square jaw look round. A beard clipped into a block can make a round jaw look square. Read the angle before you buy a frame to correct a width you may have drawn on with clippers.

The clothing difference follows that split. A round reading is served by a vertical: a V neck, an open point collar, a longline jacket worn unbuttoned. Angular or rectangular glasses add corners the outline does not already have. A square reading is served by a curve: a scoop, a camp collar, rounder glasses, and hair or beard texture that passes the jaw instead of ending in a second straight edge. Using the round prescription on a square jaw repeats the problem you meant to solve, and the reverse does the same. If the scores are close, try one vertical and one curve in the same color and keep the outline that looks quieter.

Heart against diamond

Heart and diamond both narrow toward the chin, which is why quizzes swap them. Heart’s forehead is clearly wider than its jaw, forehead to jaw near 1.28, and the cheeks are about as wide as the forehead, cheek to forehead near 0.98. The chin is narrow, about 0.32 of the cheeks, and the chin angle is the sharpest of the six, near 104 degrees. Diamond’s cheeks are the wide point, cheek to forehead near 1.22. The forehead is only slightly wider than the jaw, near 1.06, and the jaw itself is narrow, near 0.74, with a chin angle around 116 degrees rather than the heart’s sharper point.

If you have been using the heart name because the chin is small, check cheek to forehead. A value near 1.22 is the diamond pattern. A value near 1.0, with forehead to jaw near 1.28, is the heart pattern. The styling difference is practical. Heart adds width low: a boat neck, an open collar, glasses lighter along the bottom, hair fuller from the ears down and quieter at the temples. Diamond adds width at the forehead and the jaw and keeps the cheek smoother: frames with a defined top edge, volume at the brow and beside the chin, and a neckline that does not stop in a hard line right under the cheekbones. A high mock neck can do that last thing, drawing a stripe at the widest point.

Oval is not the leftover bin

Oval is the junk drawer of informal sorting. If a face is not a cartoon of one of the other five, a quiz calls it oval and moves on. This classifier does not. Oval is a specific vector: length a bit greater than width on the mesh scale, jaw narrower than the cheeks, forehead similar to the jaw, chin angle in the middle of the set. A long face with length near 1.68 is oblong even when the jaw is gentle. A wide jaw with a sharp angle is square even if someone once said you were basically oval. A narrow chin with a wide forehead is heart. Cheeks that clearly outrun the forehead are diamond. When the scores are close, the note says which two patterns are near. It does not dump the remainder into oval to be polite.

That matters because oval styling is mostly permission. Most necklines and most frame shapes can sit on that balance. The work moves to palette: which metal, which collar color, which hair value. If the true nearest shape is oblong, that permission is the wrong gift. You would skip the horizontal, the taller frame, and the side volume, and then wonder why the length still dominates. If the true nearest shape is square, permission to wear a heavy square frame repeats the jaw. The junk-drawer label feels kind. It hides the ratio you could have used.

What the label is for

Use the shape to choose a line. Use the season to choose the color of that line. A boat neck in a hue that grays the skin still fails at the collar. Undertone, value, chroma, and contrast are separate measurements. Season pages such as true autumn hold the swatches for one reading. Contrast levels explain why a dark frame and a light frame are not interchangeable even when the frame shape is right. Hair dye is the same split: the cut can answer the shape, and the dye answers the season, which is why hair color and seasons is a different page from the shape pages.

The practical test is small. Put on the neckline the shape page suggests, in a color the season already accepts, and look at the outline from the shoulders up. Then try the neighboring shape’s neckline in that same color. Keep the one that balances the ratio you can see. Glasses follow the same test. The frame should reach the width of the face, and its shape should add the corner or the curve you are short of. Hair follows it again. None of this requires a new personality, and none of it is different for one gender than another. A camp collar and a short beard are both lines. They are not gendered rules with separate geometry.

One face, three lines

Take a straight-on photo that the analyzer calls close between oval and oblong: length a little over 1.5, jaw near 0.85 of the cheeks, forehead close to the jaw. A deep V with no width at the shoulder continues the length. A boat neck in the same knit draws a horizontal under the chin and shortens the impression. A standard point collar, buttoned, does less of either. If you add a scarf, set the mass across the collarbone rather than in a long tail down the center. That is the oblong idea applied lightly, without pretending the face is extremely long.

Change only the glasses. A narrow oval wire, smaller than the cheek width, leaves the eyes in a short band and the forehead and chin as empty length. A taller frame that reaches the temples fills more of that length. If the second score had been square instead of oblong, you would swap the taller rectangle for a rounder metal frame, because you would be offsetting a jaw angle rather than a long mid-face. The object changes when the neighbor changes. A single “best glasses” list cannot survive that fact, which is why the shape pages keep their own examples.

Hair is the third trial. A center part with flat length past the shoulders repeats a vertical. A side part with a little width at the jaw, or a fringe that covers part of the forehead, interrupts it. If you keep a beard, a shape fuller at the sides and clipped shorter in front adds a horizontal. A long pointed beard adds another vertical. Collar, then frame, then hair: that order is the method on every shape page. The specific shirts, frames, and cuts differ so the pages are not one uniform copied six times.

A photograph the mesh can read

Face the camera. A turn narrows the width the mesh can see, and a tilt changes the apparent length. Use daylight from a window rather than a ceiling spot, for the color reading as much as for the shape. A broad smile pulls the cheeks outward and can lift the jaw corners, which moves jaw-to-cheek and the chin angle together. A relaxed face gives the landmarks a quieter job. If a fringe covers the upper forehead, the mesh may still estimate landmark 10, but the estimate is less steady than it is on visible skin. Pin the hair back for the photo if you want the point placed on the forehead. Put the fringe back afterward. The measurement and the haircut are different moments.

If the notes say the shape is close, repeat the photo once in the same light before you buy frames. Two close calls that name the same neighbor are a stable answer. Two close calls that swap the neighbor mean the margins are thin, and you should dress for the ratios you can see shared by both names. A heavy beard over the jaw is a reason to treat a single reading as provisional, because the corners the angle depends on are partly hidden. None of these cautions makes the label decorative. They keep a measured category from being asked to do more than the landmarks support.