Face Form Finder

Jawline Shape: The Three Measurements Behind Every Label

Most jawline guides hand you a list of shape names and a sentence about each. None of them gives you a distance. This page starts with the three readings a jaw is actually measured by, in degrees and millimetres, taken from 78 people whose jaws were traced on panoramic films. The shape names come further down, and so does the reason a millimetre figure for a jaw has to travel with the method that produced it.

The spread column is the one to read first. A jaw angle of 107 degrees and a jaw angle of 145 degrees are both inside this group, and those two sit 38 degrees apart, wider than the span that gets quoted as a normal jaw angle. An average is the middle of a spread like that, not the shape of it.

The two sides of one face are also not two independent jaws. Across the 78, the right and left gonial angles track each other at r = 0.795 and the two ramus heights at r = 0.895. Close, but not identical, which is why a jaw that looks level in a mirror can still measure a little uneven.

The angle and the width move against each other as well. As the gonial angle opens, the bigonial width tends to narrow, at r = −0.338 against the right angle and −0.323 against the left. A jaw with a closed corner carries its width further back, which is the same thing the shape names are trying to describe.

What each of the three is

Each row is one landmark that gets measured on an image. Two of the three meet at the same corner of the jaw, which is why they get mixed up.

The gonial angle is the corner where the lower border of the jaw turns upward into the vertical part behind the ear. In profile it is the angle between those two lines. A closed angle, nearer 90 degrees, makes that corner visible from the front. An open angle rounds it off and the corner stops showing.

The bigonial width is the straight line between the two jaw corners, taken from the front. It is the widest point of the lower face, and it is the reading the phrase wide jaw is about.

The ramus height is how far the jaw corner sits below the top of that vertical part. A long ramus drops the corner lower on the face; a short one lifts it toward the ear. This is the reading that decides whether a wide jaw reads as long or as square.

The same three readings, taken a second way

The figures above come from jaws traced on flat panoramic films. The same landmarks have also been measured on three-dimensional scans, in a set of 280 adults aged 20 to 79, and the two sets do not match.

Bigonial width reads 134.9 mm in the first table and 80.68 mm in the youngest group of women in the second. Ramus height goes the other way, at 48.4 mm against 69.75 mm. Both are the span between the same two named points on the jaw.

Neither set is a mistake, and the gap is far too large to be rounding. One was read off a two-dimensional film and the other off a three-dimensional scan, and the horizontal readings are the ones the flat film handles least well. A jaw width taken from a film and a jaw width taken from a scan are two different quantities that happen to share a name.

That is the part worth carrying away. A millimetre figure for a jaw is only usable with the method attached, and a page that gives you one number for jaw width and stops has left out the part that decides whether the number applies to you.

What the same jaws do over fifty years

Read down the second table instead of across it and the lower jaw has a direction.

Bigonial width gains about 4 mm in women and about 7 mm in men between the youngest and oldest groups. Ramus height loses about 5 mm and about 4 mm over the same span. The angle moves the other way for women, opening about 4 degrees, and barely moves at all for men.

So the lower jaw widens while the vertical part behind it shortens. The whole skeletal change is around 5 mm, and the same scans point to soft tissue rather than bone as the larger part of how a jawline reads with age. The bone under a jawline is fairly stable; what changes most is what sits on top of it.

The shape names, and what they are built on

The names that turn up on jawline charts are shorthand for how the three readings sit together, not separate categories.

Square is a closed angle, so the corner shows from the front, with the jaw width running close to the cheekbone and forehead widths.

Round is an open angle, so the corner is gone and the outline runs on a curve from ear to chin.

V-line, or triangular, is a width that narrows toward a pointed chin while the angle stays open.

Rectangular, or oblong, is a width that holds all the way down on a face that runs long.

Diamond is a face whose widest point sits at the cheekbones rather than at the jaw.

None of those names arrives with a number attached in either of the sets above, and that is not an oversight. Jaws get measured landmark by landmark, on people who were never sorted into shape groups, so there is no figure in them for the angle of a square jaw or the width of a V-line one. A list can give you the name and a measurement can give you the distance. The step that joins the two is yours.

What these landmarks are, and what they are not

The three readings above are imaging landmarks. In both sets they were taken on images — traced on flat panoramic films in the first, measured on three-dimensional scans in the second — by people trained to place each point on a radiograph.

That is not a formality. The gonial angle is the angle between two lines that meet at the back corner of the jaw, and that corner sits under the soft tissue of the cheek and the ear. The bigonial width is the distance between the two corners, and a photograph flattens exactly the depth that separates them. The ramus height runs from that corner up to the top of the vertical part, which sits inside the face rather than on its outline.

A mirror and a photograph are still worth something: they let you watch the outline as a whole, and see how it shifts when the head tilts. They cannot put a number on any of the three, and nothing here is a method to carry out at home and set against the tables above.

Read the figures as what they are: averages from two named groups, with the method attached.

What these numbers cannot tell you

The four readings that build a face shape from the brow ridge down are in Face Shape Chart, and the landmarks most guides ask you to take are worked through in What Is My Face Shape?. The same approach applied above the jaw is in Nose Shape Chart and Eye Shape Chart.