Why you do not have one size

If you make or sell shoes and you want to help us solve this, please reach out. Accurate charts, published per model, would fix most of what follows.

I do not have a shoe size. I have a foot, and a list of numbers that different companies use to describe it. Depending on whose shoe I am standing in, my foot is a 41, a 42, or a 43.

That is a thing you can feel in a shop and never quite prove. However, we are now in an unusual position to prove it. This is what we've found.

On paper this is a solved problem

Read the Wikipedia page on shoe size and you would think this was settled a century ago. It is a page full of standards.

A European size steps by one Paris point, which is two thirds of a centimetre, 6.67 mm. A UK or US size steps by one barleycorn, an old English unit of a third of an inch, 8.47 mm. There is a third system, Mondopoint, standardised as ISO 9407, which does the obvious thing and describes a shoe by the foot length and width in millimetres it is meant to fit. There is even an ISO specification for converting between the systems.

The page is however honest enough to note that tables differ between shoemakers and shops, and that shoe size systems "are not fully standardised".

In this article we dive into what this translates to in the real world.

What we looked at

This analysis is based on the size charts we hold for 16,957 models across 69 brands. Skechers, Stuart Weitzman, Puma, Reebok, Stella McCartney, Nike, Converse, Clarks, Vagabond and Under Armour are among the brands with the most models behind them.

Most products link to a generic brand size chart, and we ended up with 1,279 unique size charts. The figures below compare brands and models across these 1,279 charts.

All of it was collected during 2026, between January and August, through a community effort.

The deep dive is based on official size charts only. Each chart is the brand's own published answer for a specific shoe, which is what makes the comparisons below possible.

It is worth noting that we're only looking at official charts published by brands. The picture changes substantially when you expand it to physical and online retailers. We encourage further analysis of this space.

These are the charts as the brands published them between January and August 2026, and brands revise them. We keep the page each one came from. If you work for a brand named here and think a figure misrepresents your chart, write to us and we will check it against the source and correct it.

About 3.66% of the data we collected for this analysis is unusable, either because the two ends of a range are the same number or because the length is too short to be a foot. Size charts are published in a wide variety of formats, which makes collecting them at this scale difficult. Everything below excludes these.

The same number covers 27 mm of foot

Take one label, EU 42, and ask each brand what foot it fits. Across the 51 brands where we hold at least fifteen models, the answer runs from 260 mm to 287.5 mm, a spread of 27 mm.

A Paris point is 6.67 mm. So the single label "42" covers a little over four full sizes of actual foot, depending on who printed it. A foot that Clarks calls a 42 is more than three sizes smaller than a foot Skechers calls a 42, and both brands are describing their own shoes correctly.

The same foot answers to five numbers

Turn it around. Take a 265 mm foot and ask what it is called.

Nine models in ten come back somewhere between EU 39.5 and EU 42. Across everything we hold the answers run from 39 to 43. Five numbers, one foot, and every one of them is correct on the chart it came from.

The same objection applies here as above, that some of this is the men's and women's split rather than brands disagreeing. It is not enough to explain it. Comparing only models sold as men's, the EU 42 spread across brands is still 23 mm, and comparing only women's it is 22 mm. Brands disagree with each other whichever way you slice it.

This is why "what size are you" is a question with no answer. And why the much easier question to ask is which shoes currently fit you well.

Brands do not agree with themselves either

I expected brands to disagree with each other. What I did not expect was how often a brand disagrees with itself.

Skechers publishes charts where EU 42 fits a foot of 268 mm on one model and 285 mm on another, across the models it sells under one name. Sergio Rossi and Moncler each span 20 mm the same way, and Cos 14 mm.

There is of course a good reason for spread to exist. A running shoe and a boot from the same company are built on different lasts, so an accurate chart for one is the wrong chart for the other. The question then is how to communicate that to consumers in a managable way.

Of the 51 brands measured above, 18 publish more than one chart across their range. The other 33 give the same answer for everything they sell. Ancient Greek Sandals goes furthest, with a chart recorded against 448 separate models, then Steve Madden with 384, Vagabond 373, Castañer 362, Cole Haan 214, Mou 197 and Santoni 165.

The men's and women's scales measure the same foot

This is the part I most wanted to check.

Some brands publish a men's chart and a women's chart, both giving foot length in millimetres. That lets us line up the rows where the two charts describe the identical foot and compare only the number printed next to it.

In US sizing the number is different every single time. Not most of the time. Every time. A woman's foot is given a higher number than a man's foot of exactly the same length, on every brand that publishes both scales.

The Wikipedia page describes two competing conventions here: under one scale a women's size is a men's size plus 1, and under the other it is plus 1.5. Our data holds neither of them across the industry. It holds one of them, rigidly, inside each brand:

Not one of them varies. Look at the last column: Nike prints its two scales against 46 different foot lengths, from the smallest shoe it sells to the largest, across 289 models, and the gap between the men's number and the women's number is 1.5 at every single one of them. Caterpillar is 2.0 at all 19 of its. A 263 to 269 mm foot is a men's 6.5 and a women's 8.5 at Converse, and an 8 at Nike, Vans, Diadora and Under Armour.

Each of these is a fixed number added to a label. Because the brands picked different ones, a foot that a brand calls a men's 6.5 becomes a women's 8.5 at Converse, an 8 at Vans and Under Armour, and either a 7.5 or an 8 at Nike.

In EU sizing, 155 of 287 comparisons differ, and the direction reverses. A woman's foot of a given length is given a number 0.56 lower on average. New Balance runs 0.95 lower over 19 comparisons and UGG 0.97 over 15. Columbia is a flat 1.0 the whole way up its chart, over 8. Timberland at 0.93, Merrell at 1.64 and Skechers at 1.86 each rest on seven. Allbirds puts a 260 to 270 mm foot at EU 42 on its men's chart and EU 40 on its women's.

In UK sizing most brands print the same number for both, and there is no consistent gap at all.

Read those three together. The same brand, measuring the same millimetres, prints a higher number for women in one system, a lower number in another, and the same number in a third. Whatever those numbers are describing, it is not the foot.

There is a fair objection to make here. Men's and women's shoes are built on different lasts, often narrower at the heel and different in volume, so a brand could reasonably answer that two scales describe two genuinely different products.

The shape of the numbers argues against that. A last difference varies by model and by size. What we see is a constant: 2.0 at Caterpillar and 1.5 at Nike, holding at every size from the smallest to the largest, on every model. Whatever a different last does to a shoe, it does not do it in exactly the same amount at every length, on every shoe, to the half size.

I will not claim to know or understand why each brand settled where it did, because our data holds charts and not motives. What the data does settle is that the offset is applied to the label rather than derived from the foot, which is why we have to keep two charts for the same shoe and ask which one you are buying from.

What we do about it

None of this is fixable by creating a new standard, because the standard already exists. Mondopoint has described shoes by the millimetres of foot they fit since the 1970s, which is exactly what the charts underneath all of this are keyed on. It is not what the global industry has opted for, which leaves it up to you to either become an expert on every brand or simply try the shoes on.

Rather than trying to convince a vast global industry to implement yet another standard, we think we can solve it with a service that only uses charts from official sources, and that removes the guesswork and the uncertainty. And what's even better: if we all grabbed a pair of shoes and shared how they fit, we could remove the need to look at size charts all together.

If you own a pair that fits you well, adding it to your shoe rack takes us all one step closer to this vision. This is what GetSize is all about.

Best regards,
Thomas

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Correction, 5 September 2026. The first version of the men's and women's table matched rows across each brand as a whole, which pooled together charts belonging to different shoes. That made two brands look inconsistent when they are not: Nike was published as +1.35 varying between 1.0 and 1.5, and Caterpillar as +2.0 varying between 1.0 and 3.0. Matching within each product instead, so that the two rows being compared always come from the same shoe, Nike is +1.5 and Caterpillar is +2.0, with no variation anywhere. The table above has been rebuilt that way. The correction removes the only counterexample we had and makes the finding a stronger one: every brand that publishes both scales adds a fixed number to the label.