Shoe Size Conversion Guide for Online Shopping

By Rick Oosterling · Published on February 6, 2026

How to use size charts without pretending they are perfect.

Shoe size conversion looks easy until you actually buy shoes from another region. One chart says EU 42 is UK 8 and US men 9. Another says something slightly different. Then the shoe arrives and still feels off.

The first thing to accept is that no simple chart can solve brand differences completely. The shape of the last, the width of the shoe, the style of the footwear and the manufacturer's own sizing habits all affect the final fit. Still, a sensible size converter can cut through the chaos and give visitors a starting point that is far better than guessing.

The right design is practical. Keep the comparison tool near the top. Under that, tell the truth: use the chart as a range, then compare brand notes and return policy.

Why shoe size charts disagree

There are four sizing systems in common use, and they were never designed to line up neatly. EU sizes use the Paris point, where each full size is two thirds of a centimetre (about 6.67 mm). UK and US sizes use the barleycorn, where each size is one third of an inch (about 8.47 mm), and they start counting from different zero points. US women's sizes are usually the US men's number plus 1.5. Centimetre sizing (sometimes labelled Mondopoint) simply states the foot length directly.

On top of those system differences, every brand cuts its shoes around a different last (the foot-shaped mould). Two shoes both marked EU 42 can fit a full size apart if one brand runs narrow and the other runs wide. That is why a conversion chart is a starting point, not a guarantee.

Measure your foot first: centimetres are the honest anchor

The most reliable number is your own foot length in millimetres, because it removes the guesswork between systems. Measure it once and you can shop in any region.

  • Stand on a sheet of paper with your heel against a wall, in the evening when feet are largest.
  • Mark the tip of your longest toe and measure heel to mark in millimetres.
  • Measure both feet and use the larger one.
  • Add 5 to 10 mm of toe room for walking shoes, slightly more for running shoes.

Approximate size cross-reference (men's)

Use this as a range, then confirm against the brand's own chart. The foot-length column is the value to trust when sizes conflict.

Foot lengthEUUKUS men
24.5 cm3966.5
25.0 cm406.57.5
25.7 cm417.58
26.3 cm4288.5
27.0 cm4399.5
27.6 cm449.510.5
28.3 cm4510.511
29.0 cm461112

For US women's sizes, add roughly 1.5 to the US men's number (US men 8.5 is about US women 10). For children's sizes the systems diverge even more, so always measure foot length and check the brand chart.

Where Japan and Korea fit in

Japan and Korea make the cross-reference simpler, not harder, because both label shoes by foot length directly. Japan prints the size in centimetres (a 25.0 cm foot is JP 25.0). Korea prints the same length in millimetres (that same foot is KR 250). So once you know your foot length, JP and KR need no formula at all: JP equals the cm number, KR equals the cm number times 10.

Foot lengthEUUS womenJapan (cm)Korea (mm)
22.3 cm365.522.3223
23.0 cm37623.0230
23.7 cm38723.7237
24.5 cm39824.5245
25.0 cm40925.0250
25.7 cm419.525.7257
26.3 cm421026.3263

The right two columns are the same physical length written two ways, so a Japanese 25.0 and a Korean 250 are the identical shoe; only the unit on the label changed. That is the cleanest reason to shop by foot length: in JP and KR systems the size number is your measurement, with no zero point or barleycorn step to convert.

Convert between EU, UK and US step by step

Say a German store lists a shoe as EU 43 and you normally buy US. From the table, EU 43 is about US men 9.5 and UK 9, which matches a foot length near 27 cm. Enter the size in the converter to see all systems at once, then check the brand's notes before ordering.

How to buy online without getting burned

  • Anchor on foot length in cm, not on the size number you usually wear.
  • Read the brand's size notes and search reviews for "runs small" or "runs large".
  • For wide feet, size up by a half rather than squeezing into the nominal size.
  • Check the return policy before buying, especially across borders where returns cost more.

Frequently Asked Questions

How do EU and US shoe sizes line up?

They never sit a fixed gap apart, because the systems use different step sizes: an EU full size is 6.67 mm (two thirds of a centimetre) while a US half size is about 4.23 mm. As a rough men's rule, US men size is roughly the EU number minus 33.5, so EU 42 is about US men 8.5 and EU 43 is about US men 9.5. The gap widens at the extremes, which is why the foot-length column, not subtraction, is the value to trust.

Why do two brands fit differently at the same labelled size?

Each brand builds its shoes around its own last, the foot-shaped mould, and on width as well as length. Two shoes both marked EU 42 can fit a full size apart, and one EU size is 6.67 mm, so that is real space at the toe. Width adds to it: a shoe cut for a narrow last can feel a half size short on a wide foot even when the length matches.

How do I measure my foot length to pick a size?

Stand on paper with your heel against a wall, in the evening when feet are at their largest, mark your longest toe, and measure heel to mark in millimetres. Do both feet and use the larger one, then add 5 to 10 mm of toe room for walking shoes (a little more for running). A 250 mm foot plus 8 mm room points to a 258 mm internal length, which lands near EU 40 to 41.

Do Japan and Korea sizes need a conversion formula?

No. Both label by foot length, so there is no zero point or barleycorn step to undo. Japan prints the length in centimetres and Korea prints it in millimetres, meaning JP equals your cm number and KR equals that number times 10. A 25.0 cm foot is JP 25.0 and KR 250, the identical shoe written two ways.

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