Article — US to UK Shoe Size Converter
US to UK Shoe Size Converter: men, women, kids
US men's shoe sizes run one full size higher than UK men's. US women's sizes run two sizes higher than UK women's. A US 10 men is UK 9 men is EU 43, all about 27 cm of foot length. The international standard ISO 9407 (Mondopoint) uses foot length in millimeters as the underlying physical reference.
How US and UK shoe sizing works
Both the US and UK systems trace back to the medieval English barleycorn, defined as 1/3 inch (8.47 mm). One full shoe size, in either country's scale, equals 1/3 inch of foot length. A half size equals 1/6 inch (4.23 mm). The scale increments are identical; the zero point is different.
The Brannock Device — the metal foot-measuring tool in every US shoe store since 1927 — formalized the US scale. Charles Brannock patented his sliding device in 1925; Brannock's system uses size 1 as a 7-2/3 inch (19.5 cm) foot, with each subsequent size adding 1/3 inch. The UK scale starts a full size lower (UK 0 = 4 inch foot, newborn territory). Adult UK runs 6 to 13 for men, 3 to 9 for women; the US scale shifts each adult size up by one for men and by two for women.
The 1/3-inch shoe-size increment dates back at least to a 1324 English statute fixing 3 barleycorns to an inch. Edward II's rule made a barleycorn the standard granular unit for measuring foot length. The Brannock Device, an American invention from 1925, kept the barleycorn alive in modern shoe stores nearly seven centuries later.
The US to UK shoe size offsets
The three offsets you need to know cover most adult and youth conversions:
- US men to UK men = subtract 1. US 10 = UK 9.
- US women to UK women = subtract 2. US 8 = UK 6.
- US men to US women (same foot) = add 1.5. US 9 men = US 10.5 women.
- UK kids to US kids = roughly +1, with a discontinuity at UK 13 = US 1.
- EU to US men = subtract about 33. EU 42 ≈ US 9 men.
- EU to UK men = subtract about 34. EU 42 ≈ UK 8 men.
These offsets are reliable for standard-width adult shoes. Brand variation can add another half size in either direction. Width grading (B, D, E, EE in US; F, G, H in UK; numeric Mondopoint width in EU) sits perpendicular to length grading and uses its own offsets.
Men's shoe size conversion
Men's sizing is the most consistent across systems. The 1-size US-UK offset has held since the early 1900s. EU sizes increment more finely than US/UK above size 41, with half-size EU steps (42, 42.5, 43, 43.5) where US/UK use whole sizes.
Women's shoe size conversion
Women's sizing is messier than men's. The US-UK offset is 2 sizes instead of 1, the result of historic UK women's last design treating women's shoes as a downward extension of men's. A US 8 women maps to UK 6 women — check foot length, not the label. EU sizing uses the same Paris point scale across men, women, and kids. The US women's scale also runs 1.5 sizes above the US men's scale at the same foot length: a 24 cm foot is US 6 men but US 7.5 women.
US 6 UK 4 · EU 36.5 · 22.5 cmUS 7 UK 5 · EU 37.5 · 23.5 cmUS 8 UK 6 · EU 38.5 · 24.1 cmUS 9 UK 7 · EU 40 · 25.1 cmUS 10 UK 8 · EU 41 · 25.9 cmKids sizing
Kids shoe sizing runs on its own scale that resets where adult sizing begins. US kids sizes count up from 0 (newborn) through 13, then start over at 1 in the toddler / youth scale (which runs to 7 before adult men's begins at 7.5). UK kids similarly count to 13, then restart at 1.
The mapping has a quirky discontinuity: UK 13 youth = US 1 youth = 20 cm foot. Going up a size from US 13 to US 1 is bigger, not smaller — the label restarts but the foot keeps growing. Many parents trip over this when buying online and the shoe comes too small.
When your child outgrows US 13 youth, the next size up is US 1 (sometimes labeled "1Y" or "1 little kid"). It is bigger than 13, not smaller. UK 13 youth has the same issue: next is UK 1 (adult).
EU and Mondopoint
EU shoe sizing uses the Paris point system, where one size = 6.67 mm (2/3 cm). This is the standard across France, Germany, Italy, Spain, and most of continental Europe. The international standard ISO 9407 introduces Mondopoint: foot length in millimeters, optionally followed by a width code. Mondopoint is the underlying reference for NATO military boots, ski boots, climbing shoes, and many performance running brands. Japan and Korea label everyday shoes in Mondopoint directly: a JP 26 is a 26 cm foot.
Measuring your foot
The most reliable size signal is foot length in centimeters. Stand on a piece of paper with full weight on the foot, mark the back of the heel and the tip of the longest toe, measure the distance. Repeat for the second foot — 60 percent of adults have different-size feet. Add 5 to 10 mm of toe room. Size late in the day, when foot swelling adds 3 to 8 mm. Athletic shoes for running need more room (10 to 15 mm) than dress shoes (5 mm).
If you're between sizes, choose the larger size for athletic shoes and the smaller size for dress shoes. Athletic lasts have stretch and lacing to take up extra space; dress shoes don't and will rub at the heel.
Common shoe size conversion mistakes
The first mistake is using men's offsets for women's shoes. US to UK is 1 size for men and 2 for women. Confusing the two puts you a full size off. Always check the gender label before applying any offset.
The second is reading EU sizes as inches or US sizes. EU 42 is not US 42. EU 42 is roughly US 9 men or US 10.5 women. The numerical similarity between EU and small dress sizes (e.g., EU 36 = US women 6) makes it easy to assume a 1:1 mapping that doesn't exist.
The third is ignoring brand variation. Same labeled US 9 from Nike, Adidas, and New Balance can vary by half a size or more. Nike runs about 0.5 small in their running line; some Italian dress brands run 0.5 large. When ordering online, check fit-note reviews for the specific model — they're more reliable than the size chart.