Shoe Size Converter

Pick the men's, women's or kids chart, choose the system your size is written in, and the converter returns the matching sizes in the other two systems along with the nominal foot length behind that row, in centimeters and inches. A short table shows the neighboring rows, because shoe conversion is never precise enough to trust a single cell. ISO 19407, the standard that aligns the major sizing systems, says exact conversions cannot be given to whole or half sizes and calls its own tables a guideline. Every chart, this one included, is an approximation, and brands cut the same nominal size differently.

How the conversion works

Shoe sizes are not measurements. They are rungs on a ladder, and the systems disagree about where the ladder starts and how far apart the rungs sit. British and American sizes climb in steps of one barleycorn, an old English unit of a third of an inch, about 8.47 millimeters. European sizes climb in Paris points of two thirds of a centimeter, 6.67 millimeters. The classic last-based definitions are:

UK size = 3 × last length in inches − 25

EU size = 1.5 × last length in centimeters

The last is the foot-shaped form a shoe is built around, and it runs longer than the foot inside it: ISO 19407 takes the difference to be two grading steps, and for children's shoes it sets the effective last length at eight percent over the foot. The US men's scale is the UK scale shifted up by one, 3 × last length − 24, and the women's scale used here sits at UK plus two. The two ladders also start from different zero points, 101.6 millimeters for the UK and 99.5 for the US. The UK scale spends its first 13 sizes on children's shoes before restarting at 1, which is why the kids chart puts UK 13 beside US 1.

The calculator does not run these formulas. It looks your size up in a fixed chart, and a size no chart row sits close enough to produces a message naming the sizes around it rather than a guessed conversion.

A worked example by hand

Take the default, a men's US 9. The chart row reads UK 8, EU 41, foot length 26.2 cm / 10.3 in. The ISO 19407 foot-based formulas cross-check it. UK size is foot length in millimeters divided by 8.47, minus 23: 262 divided by 8.47 is 30.9, minus 23 gives 7.9, which rounds to UK 8, matching the chart. The EU formula is foot length divided by 6.67, plus 2: 262 divided by 6.67 is 39.3, plus 2 gives 41.3. Here the sources drift apart: the retail chart behind this converter prints EU 41, the ISO conversion table places UK 8 at EU 41.5, and ISO notes that shops often label a UK 8 as an EU 42 while calling 41.5 the more technically correct figure. Three defensible answers across a full size step: hence the neighboring rows.

From barleycorns to numbered lasts

The barleycorn entered English law long before it reached shoes. A statute of uncertain date, which popular histories place in 1324 under Edward II, defined the inch as three grains of barley, dry and round, laid end to end; the same idea appears in the tenth-century Welsh laws of Hywel Dda. From it grew a durable legend that Edward II set shoe sizes that year. It does not hold: the statute concerns the inch, not footwear, and nothing links Edward II to any shoe standard.

The first written record of an English shoe-sizing system comes in 1688, when Randle Holme III described in The Academy of Armory and Blazon quarter-inch increments starting from a child's shoe five inches long. The third-of-an-inch step behind modern UK and US sizes is documented later still: Today I Found Out traces the first hard record to Robert Gardiner's Illustrated Handbook of the Foot, London, 1856, while SATRA, the footwear research body, notes shoemakers of that era were split between third-inch and quarter-inch steps. American sizing settled after the New York businessman Edwin Simpson proposed a standard set of lasts in 1880, adopted across the US industry about a decade later, and half sizes appeared in the same period. The continental unit took a different path: SATRA calls it an outgrowth of the metric system, and Wikipedia's Paris point entry dates it to French shoemakers of the early 1800s, whose two thirds of a centimeter sits very close to a quarter of the old French inch.

The Brannock device

Charles F. Brannock (1903–1992) of Syracuse, New York, son of a Park-Brannock Shoe Store co-founder, worked out his foot-measuring device while a Syracuse University student. By the Smithsonian's account, he began manufacturing it in 1925 after a trial run in his father's store and offered it to shoe retailers in 1926, first as a rental and then for sale. The patent record is often misquoted: the first patent, US 1,682,366, was filed November 4, 1925 and granted August 28, 1928, and the second, US 1,725,334, was filed September 17, 1927 and granted August 20, 1929, so the familiar claim of a 1925 patent quotes a filing date. The device takes three measurements at once, heel-to-toe length, arch length from heel to ball, and width, and a conversion chart carries only the first, which is why a chart never replaces a fitting.

Mondopoint and the ISO standards

The one system that refuses the ladder game is Mondopoint, defined in ISO 9407:2019. A Mondopoint shoe is marked with the foot length itself in millimeters, width optional, so a 275 boot is cut for a 275-millimeter foot. ISO 19407 cites DIN 66074-2 for grading intervals of 5 millimeters, or 7.5 in some specialist footwear, and records the trade practice of treating 10-millimeter steps as whole sizes and 5-millimeter steps as half sizes. Mondopoint has been adopted for military and ski-boot use, and China, Japan and Korea designate shoe length the same way, Japan sometimes in centimeters. Conversion has its own standard, ISO 19407, a separate document despite the similar number. It began as a technical specification, ISO/TS 19407:2015, which the first full edition, ISO 19407:2023, cancelled and replaced; the 2023 text aligns the Mondopoint, European, UK, American and East Asian scales on the one quantity they share, foot length.

Why brands still disagree

Two US women's scales coexist. The standard scale, used here, places women's sizes at UK plus two, one above men's; the common retail scale places them at men's plus one and a half, so the same foot can honestly carry two US numbers half a size apart. By the ISO foot-length formula a 240-millimeter foot lands on UK 5.5, which is a women's 7.5 under the convention used here and a women's 8 on the common scale. Kids sizes are shakier still: ISO puts the US children's scale usually half a size above the UK scale, while retail charts show a full size, so treat kids output as approximate; between its five anchors an EU value returns the neighbors. EU markings may derive from last length or foot length depending on the country of origin, which ISO cites as a further source of differing labels. The chart's publisher warns its tables are a best interpretation that may differ across manufacturers and brands. When two systems disagree, measure the foot from heel to longest toe while standing and let the foot length column arbitrate.

Assumptions and conventions

The data is a fixed chart from the retail tables published by calculator.net, which pair each size with a foot length, cross-checked against ISO 19407:2023. The men's chart covers US 6 to 14, the women's US 4 to 12, and the kids chart five anchor sizes from a child's 10.5 through youth 7. Matching takes the nearest row within a quarter size for US and UK entries and half a size for EU, ties to the smaller size, tested row by row rather than against a column's span, so every listed size resolves, kids US 10.5 included, though it sits below kids US 1; a value no row is that close to, men's EU 42 among them, names what the chart does carry, the two sizes on either side, the range past either end, or, on the kids US and UK scales, every anchor. The kids chart keeps its five anchors because the source lists no rows between them. Women's US sizes follow the UK plus two convention, which matches both the ISO offset and the retail anchors. Kids sizes follow the retail chart's full-size offset rather than ISO's usual half size. EU values are the chart's whole numbers, within half a size of ISO's for adults. Inches are derived from the chart's centimeter figures at 2.54 centimeters to the inch. Charts last checked August 2026. None of this makes a converted size exact; it makes it a well-sourced estimate to try on.

Frequently asked questions

What is my EU size if I wear US men's 9?

Somewhere between 41 and 42 depending on the brand. The retail chart this converter uses puts US men's 9 at EU 41, the ISO 19407 conversion table puts the equivalent UK 8 at EU 41.5, and ISO notes that shops often label a UK 8 as an EU 42 even though it considers 41.5 more technically correct. If a brand runs European, start with the 41.5 or 42 and check the foot length.

Why do UK and US sizes differ by about one?

Both scales climb in the same step of one barleycorn, a third of an inch, but ISO 19407 describes the US system as the UK system plus an arbitrary offset of one size for men's footwear and usually two sizes for women's. The two scales also start from slightly different zero points, 101.6 millimeters for the UK and 99.5 millimeters for the US, so the gap is inherited history rather than arithmetic.

Why is a women's US size about two above the UK size?

Two US women's scales coexist. The standard scale places women's sizes at UK plus two, which is men's plus one, while the common retail scale places them at men's plus one and a half. This converter uses the UK plus two convention, so a chart built on the common scale can disagree with it by half a size for the same foot.

What is a barleycorn and why does it matter for shoes?

An old English unit equal to a third of an inch, about 8.47 millimeters. It is the step between consecutive whole sizes in both the UK and US systems, which is why those scales move in thirds of an inch while European sizes move in Paris points of two thirds of a centimeter, 6.67 millimeters.

Why are ski boots sized with numbers like 275?

That is Mondopoint, the system defined in ISO 9407, which marks footwear with the foot length itself in millimeters, with width as an optional second figure. A 275 boot is cut for a 275 millimeter foot. The system has been adopted for military and ski-boot use, and China, Japan and Korea designate shoe length the same way, with Japan sometimes using centimeters.

How should I measure my foot for these charts?

From the heel to the tip of the longest toe, while standing. ISO 19407 treats foot length as the starting point of every sizing system, and the shoe last is already cut about two size steps longer than the foot, so take the raw measurement without adding any allowance and let the chart do the rest.