Article — Shoe Size Conversion Calculator
Shoe size conversion calculator
Shoe size conversion translates between four major systems — US, UK, EU (Paris Point), and Japan/Mondopoint (centimeters) — by routing through foot length. A US men's 9 is roughly UK 8.5, EU 42, and 27 cm. Women's US sizes run 1.5 above men's US for the same foot length; EU and JP do not distinguish by sex.
None of the four systems agrees on a starting point or a step size, so the math always passes through foot length. The Brannock device (US/UK) measures in thirds of an inch; the Paris Point (EU) measures in two-thirds of a centimeter; Mondopoint (JP and ISO 9407) measures directly in millimeters. This calculator converts in both directions for both sexes.
What is shoe size conversion?
Shoe size conversion answers the practical question: "I wear a US 9, what should I order from a German store?" The German store lists EU 42; an Italian site might call the same shoe 42 EU but with different fit. A Tokyo store labels it 27 cm. The number on the box differs, but the shoe is the same.
The shared anchor is shoe inside length — also called the last length — which equals foot length plus a small toe allowance. Manufacturers measure feet, add the allowance, and label the shoe in their market's system. Convert by translating each label back into foot length.
The Brannock device (1925) is still the industry standard for measuring foot length in US shoe stores. Charles Brannock invented it in his father's Syracuse shoe shop using a Tinkertoy prototype. The original tooling is still used to make new devices.
The shoe size conversion formulas
Each system has its own formula relating foot length in centimeters to the printed size:
US_men = (cm − 1.867) / 0.8467 − 0.5 UK = US_men − 1.5US_women = US_men + 1.5 EU = cm × 1.5 + 1.5JP = cm 1 Paris Point = 0.667 cmThe US scale starts at children's size 0 (3 11/12 inches = 9.94 cm of foot length) and adds 1/3 inch per size. UK starts one size earlier than US and adds the same 1/3 inch step. EU uses 2/3 cm steps from a different starting point; the numbers are larger because each step is smaller relative to inch-based steps. JP just reads off the centimeter measurement.
US, UK, EU, JP shoe size systems
The US system is Brannock-based: each size up is 1/3 inch (0.8467 cm) of foot length. Half sizes split the difference. Sizes range from infant 0 (about 9.5 cm) to men's 14 (32 cm). The UK system uses the same step size but starts one size earlier, so UK = US − 1.5 for men.
The EU Paris Point dates to 1800s French shoemaking. One Paris Point is 2/3 of a centimeter; sizes are always whole numbers because the step is already small. EU 42 fits a 27 cm foot regardless of sex. Japan's Mondopoint system (international standard ISO 9407, first published 1991) simplified everything: the shoe size is foot length in centimeters, period. The rest of the world uses Mondopoint behind the scenes — NATO procurement, athletic shoes, ski boots — even when the box lists US or EU sizes.
Men's and women's shoe size differences
The US and UK shift between men's and women's scales. A 27 cm foot is a men's US 9 but a women's US 10.5 — the women's number runs 1.5 higher than the men's for the same actual foot length. The original reason was marketing: in 1900s America, women's shoes were considered a different fashion category, and the size shift reinforced the separation.
EU and Japan never adopted the split. Athletic brands targeting unisex markets — Converse, Vans, Crocs — sometimes use US men's numbers across both sexes with women's equivalents in parentheses. Always check the brand's scale.
Brand-specific shoe size quirks
Brand fit varies even within the same system. Nike runs about half a size small — many wearers go from their normal size 10 up to a 10.5 in Nike. Converse runs half a size large, especially in the Chuck Taylor line; the same person typically takes a 9.5 in Converse. Adidas runs true to EU sizing. New Balance runs true but wider than average. Asics fits Japanese feet more narrowly than Western brands.
Italian luxury brands (Gucci, Prada) frequently run small. A US 9 buyer might need an EU 43 in Gucci even though the standard conversion would suggest EU 42. German brands like Birkenstock run wide; French brands like Repetto run narrow. The general conversion gives you a starting point — the brand's own size chart and customer reviews give you the final answer.
- Nike: runs 0.5 small; size up
- Adidas: true to EU size
- Converse: runs 0.5–1 large; size down
- Vans: true to US size
- New Balance: true, wider than average
- Asics: true to JP size, narrow fit
- Birkenstock: wide fit; narrow option (N) available
- Gucci/Prada: run small; size up half to full
Common shoe size conversion mistakes
The biggest mistake is forgetting the sex shift between US and UK. A woman wearing US 8 ordering UK shoes converts to UK 5.5, not UK 6.5 (that would be a men's UK 6.5, two sizes too big). The second is rounding too aggressively. EU sizes are whole numbers, but a US 8.5 falls between EU 41 and 42. Most brands assign the closer one — usually EU 42 for a US 8.5 men's — but always check.
The third mistake is assuming width adjustments translate. US wide sizing uses letters (D = standard men's, EE = wide). EU sizing has no letter system. Birkenstock uses N (narrow) and R (regular); Asics uses 2A, B, D, 2E, 4E. Brand-specific width systems make universal conversion impossible.
Most people's feet differ by 0.5–1 cm. Always size to the larger foot. Measure in the evening when feet are at their swollen daily maximum, while standing with full body weight on the foot.
A short history of shoe sizing systems
Medieval English shoemakers measured feet in barleycorns — 1/3 of an inch — which is why each US shoe size step still equals 1/3 inch. The 1324 statute of Edward II fixed the barleycorn at exactly 1/3 of the standard English inch and noted that a child's foot was about 13 barleycorns. The first English child size 13 (8 1/3 inches) corresponds to today's UK kid's 13.
The Paris Point system arose in 1800s France from a similar artisan tradition. Two-thirds of a centimeter is roughly the width of a fingertip — a useful tactile reference for cobblers. The system spread across continental Europe before WWII. Japan's adoption of Mondopoint in 1981 was the first major attempt to retire all the legacy systems in favor of pure metric. ISO 9407 standardized it internationally, but consumer markets stick with their familiar numbers.