Insights

Nobody has the ideal foot. That is why we built one.

Every shoe is built for a foot. The industry does not agree on how long that foot is, has rarely measured how wide it is, and almost nobody has it. On the reference foot behind VSIZE, and why every fit answer starts there.

September 2026 · Novainvent AB, Halmstad · 7 min read

Open the VSIZE demo and you can choose between three feet: ideal, narrow and broad. Same length. Same size on the box. Put them in the same shoe and you get three different answers.

That is not a quirk of the demo. It is the point of it. Every shoe is built for a foot, and that foot, the ideal foot, turns out to be a surprisingly hard thing to pin down.

The number is not a length

An EU size is a number on the last, the form the shoe is built on, and the step between sizes is 6.67 mm. But how much foot a given last is meant to hold is not in the number. It depends on the shape of the last, the allowance in front of the toes, the material and the construction, and each brand decides for itself.

So each brand publishes its own guide, and the guides differ. One of the world's largest sports brands does not make a 37 at all: its sizes step from 36⅔ to 37⅓, for feet of 225 and 229 mm. Many fashion brands place their 37 at 235 mm or more. Lay the public size guides side by side and the foot a 37 is meant for moves by a centimetre or more, in a system where a whole size is 6.67 mm.

The length is not a foot

Suppose the length were settled. The largest published foot dataset, 1.2 million 3D scans from North America, Europe and Asia, shows what remains.

It should surprise nobody that a review of the literature found 63 to 72 percent of people wearing shoes that do not match their foot in length or width.

And yet every shoe has to start from a foot

A shoe is developed on one foot in one size, typically a women's 37 or a men's 42. The sample is fitted, adjusted and approved on that foot. Every other size is graded from it by rule.

So the question is never whether a shoe has an ideal foot. It always does. The question is whether that foot was measured or imagined, and whether anyone knows how far the customers stand from it. Traditionally it has been imagined: smooth, symmetrical, proportioned by convention and experience. Some developers have begun to ground it in population data. Most have not.

The ideal foot in VSIZE

Ours is built from the same open data. For a given length, it is the statistical centre: the foot you get when every other dimension takes its typical value, described with the same measurements our scanning partner, the Instituto de Biomecánica de Valencia, extracts from a real foot. Beside it stand two more, narrow and broad: the same length, with the width moved to the edges between which nine people in ten are found.

"Ideal" does not mean better. It means the foot in the middle. And the middle is a lonely place. In 1952 the US Air Force measured 4,063 pilots on ten body dimensions to design a cockpit for the average man. Not one pilot was average on all ten. Feet are no different.

That is its role. The ideal foot is not a customer. It is the ruler. A real foot is described by how it departs from the reference, zone by zone, and a fit answer becomes a statement about this foot in this shoe, not about a number on a box.

Three feet, one shoe

Put the three in the same shoe, in the same size. The ideal foot fits as designed. The narrow foot has the right length but is not held: it slides forward, the heel lifts, and the customer sizes down, trading a width problem for a length problem. The broad foot has the right length but is pressed across the ball, so the customer sizes up and gets a shoe that is too long and slips at the heel.

Both come back marked "wrong size". Neither was a size problem.

What it gives the people who design shoes

A reference foot tells a designer where the middle is. The distribution tells them how far their customers sit from it, and that is the part the industry has rarely had in front of it.

Once it is, familiar decisions look different. A slimmer last, a lower toe box, a slip-on instead of a lace: each is also a decision about who the shoe is for. And a question usually answered by returns can be asked at the drawing board instead: of the women who will buy this shoe in a 37, which ones was it built for?

Nobody is ideal

Most people are not narrow or broad either. They are a combination nobody has a name for: broad at the ball with a narrow heel, a high instep on a slim foot.

And width is not the only way to leave the middle. The ideal foot has a straight big toe. Roughly one adult in four does not. What happens to them in a shoe that turns inward before the toe joint is the subject of the next piece.

The ideal foot was never meant to describe anyone. It is there so that everyone else can be measured.