Shoe Size Conversion Calculator
Convert a shoe size between US Men's, US Women's, UK, EU, and foot length in centimeters.
Written by Magesh | Financial Tools & Calculation Specialist · Last updated August 2, 2026
In two sentences: A shoe size conversion calculator translates your foot length into US, UK, and EU sizes using three historically different measurement systems — American and British “barleycorns,” and the European “Paris point” — which is exactly why sizes don’t convert with one clean universal formula. This guide breaks down each sizing system’s underlying formula, worked examples, and why measuring your actual foot length in centimeters is more reliable than converting a size number directly.
What Is a Shoe Size Conversion Calculator?
A shoe size conversion calculator converts a shoe size — or, more reliably, a measured foot length — between the US, UK, and EU sizing systems. Unlike converting centimeters to inches, there’s no single formula that converts a US shoe size to a UK or EU size — each sizing system was developed independently, uses a different starting point, and increments in different step sizes. This is exactly why shoes ordered from a European retailer sometimes don’t fit despite an apparently correct size conversion.
The Three Shoe Sizing Systems Explained
Cobblers in the UK used “Barleycorns” (1/3 of an inch) to measure feet, while French cobblers used “Paris Points” (2/3 of a centimeter). This historical divergence is why an EU shoe size to US conversion often results in half-sizes or awkward fits.
- US sizing: based on “Brannock” measurements developed in the 1920s, with a separate scale for men’s and women’s sizes that are offset by about 1.5–2 sizes from each other for the same foot length.
- UK sizing: uses a similar barleycorn-based system (each size step is 1/3 of an inch, or about 8.46 mm) but starts counting from a different baseline than the US scale.
- EU sizing: based on the Paris point, a unit of length defined as 2/3 of a centimeter (6.67 mm), invented by French shoemakers in the early 1800s.
The Shoe Size Conversion Formulas
Calculating US size directly from foot length (Brannock formula)
In the Brannock system, U.S. men’s shoe size = (foot length in inches × 3) − 22, and U.S. women’s shoe size = (foot length in inches × 3) − 21</cite>.
Converting from foot length to EU size
<cite index=”48-1″>European sizing is based on the Paris point, approximated as EU = foot_length_cm × 1.5 + 2.
Converting between US, EU, and UK sizes
From the EU value, for men: US = EU − 33 and UK = US − 1; for women: US = EU − 31.5 and UK = US − 2.
Worked Examples
Example 1: Converting a foot measurement directly to US size
A man’s foot measures 10.5 inches long.
US Men's Size = (10.5 × 3) − 22 = 31.5 − 22 = 9.5
Example 2: Converting foot length to EU size
A foot measures 26.5 cm.
EU Size = (26.5 × 1.5) + 2 = 39.75 + 2 = 41.75 ≈ 42
Example 3: Converting between systems for men
Using the EU 42 result from Example 2:
US Men's = 42 − 33 = 9
UK Men's = 9 − 1 = 8
Example 4: Why men’s and women’s US sizes differ for the same foot
In US sizing, women’s sizes are approximately 1.5–2 sizes higher than men’s for the same foot length — for example, a men’s US 8 equals approximately a women’s US 9.5–10. This means a shoe size conversion calculator needs to know not just the numeric size but also which gendered scale it’s using, or the result can be off by a full size or more.
Step-by-Step: How to Measure Your Foot for Accurate Conversion
Tape a piece of paper to the floor against a wall. Stand upright with your heel flush against the wall — don’t sit, since your weight needs to spread your foot out naturally. Have someone else trace the outline of your toes, since doing it yourself shifts your weight and skews the measurement. Measure from the wall (heel) to the longest toe. Measure your feet in the evening, since feet swell throughout the day and you want shoes that fit your feet at their largest.
Quick Reference: Foot Length to Size
A UK 9 is approximately 27.9 cm (roughly a US Men’s 10), and 260 mm converts to approximately US Men’s 8.5, UK 7.5, or EU 42. As a general rule, UK sizes run about 1 full size smaller than US for men, and about 2 sizes smaller than US for women, due to the different starting points used within the shared barleycorn measurement system.
Getting the Most Accurate Result From a Shoe Size Conversion Calculator
A shoe size conversion calculator is only as accurate as the measurement you feed into it, which is why starting from your actual foot length rather than an existing size number produces far more reliable results, especially when shopping internationally.
Best practices for using a shoe size conversion calculator
- Always measure both feet and use the larger one. Most people have a small size difference between their left and right foot, and a shoe size conversion calculator can only be as accurate as the measurement you provide.
- Re-measure periodically, especially for children and older adults. Foot length can change gradually with age, so a shoe size conversion calculator result based on an outdated measurement can drift from your current actual size.
- Check the specific brand’s size chart when available, since a shoe size conversion calculator gives a strong general estimate, but individual brands can run up to half a size larger or smaller than the standard conversion suggests.
- Account for shoe type. Athletic shoes, dress shoes, and boots often fit differently even at the identical converted size, so treat a shoe size conversion calculator’s output as a starting point for trying on shoes, not a guarantee of fit.
Frequently Asked Questions
Shoe size charts are based on different historical measurement systems — the Barleycorn (UK and US, sizes increasing by 1/3 inch) and the Paris Point (Europe, sizes increasing by 2/3 cm) — and men’s, women’s, and children’s shoes can all have different zero points even within the same country’s system.
Yes. The safest conversion method is your foot length in centimeters, since that number doesn’t change by country — converting an existing size number between systems always involves rounding and brand-specific variation.
No. A “true” EU 42 could correspond to a UK 8 or UK 8.5 depending on the brand’s specific mold, or “last,” and Italian dress shoes commonly run narrower than American athletic shoes at the same nominal size.
The Brannock device is the metal measuring tool used in shoe stores that measures foot length, arch length, and width all at once, and is considered the gold standard for accurately sizing hard-to-fit feet.
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In summary, a shoe size conversion calculator is most reliable when it starts from an actual foot length measurement in centimeters or inches rather than converting a size number directly, since the US, UK, and EU systems were each built on entirely different historical measurement units.
About the author: Magesh is a Financial Tools & Calculation Specialist focused on building and fact-checking online calculators across finance, retail, and everyday measurement topics.
Note: This calculator and article are provided for general educational and informational purposes only. Shoe sizing varies by brand and last shape even within the same nominal size. Always check brand-specific size charts or try shoes on when possible before purchasing.