Shoe Size Converter - Instant US, UK, EU & JP Conversion

What Is a Shoe Size Converter?

A shoe size converter turns a shoe size from one national sizing system into the matching size in another. It converts between the four systems used most often in retail: US, UK, EU, and JP (Japan). The tool also converts to Mexican (MX) and Australian (AU) sizes. Shoe size converters exist because no single numbering system is used worldwide, so the same physical shoe carries a different number in each country.

How Shoe Sizing Systems Differ

Each sizing system grew out of a different historical measuring unit, and none of them line up neatly with the others.

• US sizing is based on the barleycorn, an old English unit equal to about 8.5 millimeters (the length of a grain of barley). Each US size step is one barleycorn.
• UK sizing uses the same barleycorn unit as the US system but starts counting from a different point, so UK numbers run about half a size to two sizes lower than US numbers, depending on gender.
• EU sizing is based on the Paris point, a French unit equal to two-thirds of a centimeter (about 6.67 millimeters).
• JP sizing is the simplest of the four: it states foot length directly in centimeters. A JP size 27 fits a foot about 27 centimeters long.

Because these units are different sizes, no single formula converts perfectly between all of them. Conversion charts, built from manufacturer size tables, are more reliable than any single equation.

How to Calculate a Shoe Size Conversion

The most reliable method is to look up a size in a conversion chart, because shoe brands set their own size tables and small rounding differences build up between systems. Even so, some size pairs follow a fixed offset that holds across the whole chart used by this tool.

Men's sizes, measured from the US number:

• UK size = US size − 0.5
• JP size (cm) = US size + 18
• EU size has no single fixed offset. It runs about 33 to 34.5 above the US number, depending on the size, so a chart gives the exact value.

Women's sizes, measured from the US number:

• UK size = US size − 2
• EU size = US size + 31
• JP size (cm) = US size + 17

Children's sizes, measured from the US number:

• UK size = US size − 0.5
• JP size (cm) = US size + 6
• EU size has no single fixed offset, so a chart gives the exact value.

Example

Convert a men's US size 9 to UK, EU, and JP.

• UK: 9 − 0.5 = 8.5
• JP: 9 + 18 = 27 cm
• EU: the fixed men's offset is not exact for every size, so the chart is checked directly. For US 9 the chart gives EU 42.5 (an offset of 33.5, not the rounder 33 the rule of thumb suggests).

Shoe Size Conversion Charts

Men's Shoe Sizes (US, UK, EU, JP)

Women's Shoe Sizes (US, UK, EU, JP)

Children's Shoe Sizes (US, UK, EU, JP)

This chart covers children's sizes from US 3.5 up to US 13.5, which is the standard "little kids" and "big kids" range. Sizes below US 3.5 (infant and toddler sizes) use a separate numbering system not covered by this converter.

Mexican and Australian Shoe Sizes

Mexico and Australia each use their own conventions, which this converter also supports.

• Mexican (MX) sizes run smaller than US sizes. For men, MX size equals the US size minus 1.5 (a US 9 is an MX 7.5). For women, MX size equals the US size minus 2.5 (a US 8 is an MX 5.5).
• Australian (AU) sizes follow different rules for each group. Men's and children's AU sizes match UK sizes exactly. Women's AU sizes match US sizes exactly (a women's US 8 is also an AU 8).

Factors That Affect Fit Beyond the Size Number

A converted size is a starting point, not a guarantee of fit, for several reasons.

• Brands differ. Two shoes labeled the same size from different manufacturers can measure differently inside.
• Width is separate from length. Most size charts, including this one, measure length only. US width is marked with letters such as B, D, and EE; a narrow and a wide foot can share the same length size but need different width fits.
• Rounding varies. Manufacturers round between systems in slightly different ways, which is why two charts for the same brand can disagree by half a size.

Measuring foot length directly gives the most reliable starting size. Stand on a sheet of paper with a heel against a wall, mark the tip of the longest toe, then measure the distance from the wall to the mark in millimeters. Measuring in the afternoon is more accurate, since feet swell slightly over the course of a day.

Frequently Asked Questions

What is a US men's 9 in EU sizing? A men's US size 9 equals EU 42.5, UK 8.5, and JP 27 cm.

How do I convert a US shoe size to UK? Subtract 0.5 for men's sizes, subtract 2 for women's sizes, and subtract 0.5 for children's sizes. Because women's and men's scales use different starting points, always use the chart for the correct gender.

Is a Japanese shoe size the same as a foot length in centimeters? Yes. JP sizing states foot length in centimeters directly, so a JP 25 fits a 25-centimeter foot with no further conversion needed.

Do shoe sizes vary between brands even within the same system? Yes. A size 9 from one brand can fit differently than a size 9 from another, because manufacturers use different internal forms, called lasts, to shape their shoes. A conversion chart gives a standard starting point; brand-specific size guides and customer reviews refine it further.

Does this converter support Mexican or Australian sizes? Yes. Selecting MX or AU as the source or target system applies the offsets described above: MX runs smaller than US, AU men's and children's sizes match UK, and AU women's sizes match US.

What should I do if a converted size doesn't fit? Recheck the foot measurement first. If the measurement is correct, the mismatch is likely a brand-specific fit difference rather than a conversion error. Checking the manufacturer's own size guide, when available, is the next step.