Shoe Size Conversion Calculator

How the shoe size conversion calculator works

US, UK and EU sizes are separate counting systems laid over the same feet, so the tool converts through the one quantity they share: foot length. Whatever you type is solved back to a length in inches, and every other size is worked forward from that length. The outputs therefore agree with each other even where individual brand charts do not.

For adults it uses the foot-length form of the US men's scale that Wikipedia's shoe size article gives, S ≈ 3L - 22, together with the standard retail offsets for the other systems. Japan/Mexico and China need no men's or women's split, because both are read straight off the foot in centimetres.

Children's sizes skip the adult offsets, which only hold near adult lengths. The tool finds the child's row in the table further down, sets UK half a size under the US label, and takes EU from the Paris-point relation EU ≈ 1.5 L_(cm) + 2, where L_(cm) is the foot length in centimetres.

Worked example: a US men's 10 in every system

Enter a US men’s 10 and the calculator solves it back to a foot length of 10.67 inches, or 27.1 cm.

From that 27.1 cm foot it reads UK 9.5, EU 43, Japan/Mexico 27 and China 44. China's figure is twice the centimetre length minus 10, rounded: 2 × 27.09 - 10 = 44.2. Korea labels the same foot 270, its length in millimetres.

The same foot in women’s sizing is a US 11.5, which is why the tool keeps separate men’s and women’s fields.

Men's to women's shoe size, and back again

The men's to women's shoe size conversion US retailers use adds 1.5: a men's 8 is a women's 9.5, and a men's size 10 in women's sizing is an 11.5. The women's to men's shoe size conversion subtracts the same 1.5, so a women's 8.5 is a men's 7. That is the number to look for when you want a women's shoe size in men's shoes because a style is only stocked in men's.

One US size is a third of an inch of foot, so the 1.5-size gap is exactly half an inch:

A men's 9 and a women's 9 are not the same shoe. The women's 9 fits a foot 12.7 mm shorter, which is the most common mix-up with unisex trainers labelled in one scale only. Wikipedia also lists a second women's convention, the FIA standard, that sits one size above men's rather than 1.5, so a brand following it labels the same foot half a size lower than this tool does.

Adult shoe size charts

Both charts come straight from the calculator's formulas, one row per US half size. Use them to scan neighbouring sizes, or print one next to a brand's own chart to spot where that brand runs large or small.

Men's shoe size chart

Women's shoe size chart

Compare a women's 11.5 with a men's 10: identical 27.1 cm foot, yet UK 9 and EU 42.5 on the women's chart against UK 9.5 and EU 43 on the men's. The published women's offsets simply sit half a size lower. When a unisex shoe lists only UK or EU, read it from the chart for the scale the label came from.

Euro shoe size to US women's and men's

An EU number looks unisex on the label, but the US number you get back depends on the scale. Converting a euro size to US means W = EU - 31 for women's and S = EU - 33 for men's. EU 38 to US is therefore a women's 7 or a men's 5, and EU 42 to US is a women's 11 or a men's 9. In the other direction, a size 8 in European sizing is EU 41 for men and EU 39 for women. The calculator has one EU field and reads a typed number on the men's scale, so for a women's label take the answer from the women's column below; the women's field the tool fills in comes out half a size lower.

UK vs US shoe sizes are closer for men than for women. To convert US size to UK shoes, subtract 0.5 for men's (US 10 is UK 9.5) or 2.5 for women's (US 8.5 is UK 6); for shoe size UK to US, add the same amounts back. Like the EU field, the UK field reads a typed size as men's. For a Japanese shoe size to US, type the Japanese number into the Japan/Mexico field, since it is simply the foot in centimetres. Chinese shoe size to US works through the China field, which reverses the double-and-subtract-10 rule. Shoe sizes in Mexico and US relate through the same centimetre length, which is why the tool gives Japan and Mexico one field.

Children shoe size chart, infants to big kids

Children's sizes restart instead of continuing the adult scale. US toddler and little-kid sizes run 1C to 13.5C, then big-kid sizes begin again at 1Y. The UK children's scale sits half a size lower and restarts at adult 1 after 13.5, so a US 2Y is a UK 1.5. This is the same lookup the calculator uses in its Kids and Infants/Toddlers modes, and it forms one unisex shoe size chart: a girls' style and a boys' style with the same label fit the same foot.

At the top row the labels hand over to the adult scale: a 6Y comes out as UK 5.5 and EU 39, the same as a men's 6, which is how shops move a child into adult sizes. The lengths do not hand over as neatly. The children's table builds a 6Y for a 24.8 cm foot, while the adult formula puts a men's 6 at 23.7 cm, about 1.25 sizes shorter, because the two scales start from different zero points. For a child between the two, convert the measured foot in Adults mode rather than carrying the label across. Ages drift a lot between children too, so a fresh measurement beats the age column whenever you order without trying shoes on.

Why the numbers never line up exactly

Each system counts in a different step, which is why no shoe size conversion chart can be exact in every column at once.

Two consequences show up in the charts above. A US half size is 4.23 mm, smaller than Japan's 5 mm step, so two neighbouring US half sizes sometimes share one Japanese size: men's 8.5 (25.8 cm) and 9 (26.2 cm) are both JP 26, and men's 12 and 12.5 are both JP 29. And a Paris point is shorter than a US size, so under the strict EU formula the EU number rises about 1.27 for every US size; charts that add a flat 33, including this one, keep them in lockstep instead. Run across the men's chart, the two methods agree at men's 11 and 12 (EU 44 and 45) and drift apart toward both ends: the strict formula gives EU 35 instead of 37 for a men's 4, and EU 50.5 instead of 49 for a men's 16, so two EU charts can disagree by a size or more at the edges of the range.

Mondopoint is the one most people meet on ski boots. It labels the foot in millimetres, so a 27.5 boot is built for a 275 mm foot: the same figure as Japan 27.5 and Korea 275, and roughly a US men's 10.5 in this calculator. To convert a Mondopoint size, enter it in the foot length field as 27.5 cm.

Mistakes that throw a conversion off

Entering an insole as a foot. A shoe's inside length is longer than the foot it fits; Wikipedia puts that allowance at 13 to 17 mm. At 8.47 mm per size, 15 mm is about 1.8 sizes, so an insole typed in as foot length reads nearly two sizes big. Subtract about 1.5 cm first.

Rounding down between rows. If a measurement falls between two sizes, take the larger one. Half a size of spare room is fixable with a sock or insole; a toe box that is 4 mm short is not.

Expecting width in the number. None of these systems encodes width except Mondopoint. Two shoes with the same size can fit very differently across the ball of the foot.

Measuring sitting down. A foot carrying body weight is a few millimetres longer. Our step-by-step answer to how to measure my foot size covers the standing paper-and-wall method, measuring both feet, and how often to re-check a growing child. For a centimetre and inch check on any length, the unit converter handles it in one step.