The Ultimate Shoe Size Guide: US, UK, EU & CM Explained

There is nothing more heartbreaking than ordering the perfect pair of sneakers online, waiting two weeks for delivery, and then realizing—as you try to squeeze your heel in—that "Size 10" in the UK is definitely not the same as "Size 10" in the US.

Shoe sizing is a chaotic mess of history, geography, and math. Europe uses centimeters, the US uses "Barleycorns" (yes, really), and brands like Nike and Adidas can't even agree on what a "centimeter" is.

This guide is your Rosetta Stone for footwear. We will decode the charts, explain the widths, and show you exactly how to measure your feet so you never have to return a box again.

Table of Contents

1. ●The "Big Three" Systems: US, UK, EU
2. ●Men vs. Women: The Conversion Math
3. ●Width: The Forgotten Dimension
4. ●Tutorial: How to Measure Your Feet at Home

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1. The "Big Three" Systems: US, UK, EU

Why are sizes so different? Because they are based on completely different base units.

🇺🇸 The US & Canada System

Based on the old English "Barleycorn" unit (1/3 of an inch).

• ●The scale starts at size 1 (roughly 3.9 inches) and goes up by one barleycorn per size.
• ●Chaos Factor: Men's and Women's scales are offset. A Men's 7 is roughly a Women's 8.5.

🇬🇧 The UK System

Also based on the Barleycorn, but the starting point is different.

• ●A UK size is typically 1 size smaller than the US Men's equivalent.
• ●Rule of Thumb: US Men's 10 ≈ UK 9.

🇪🇺 The European (EU) System

Based on the "Paris Point" (2/3 of a centimeter).

• ●This is why EU sizes look like "42" or "38".
• ●Because 2/3 cm is smaller than 1/3 inch, EU sizes move in smaller increments, offering a slightly more precise fit without half sizes.

👟 Interactive Tool: Global Shoe Converter

Confused? Don't do the math in your head. Select your current size below to see exactly what it translates to globally:

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2. Men vs. Women: The Conversion Math

Sometimes the best colorway drops only in Men's sizes, or a woman finds a Grail sneaker in the Men's section. Can you wear it?

Yes, but you need to convert.

The General Rule (US Sizes):

• ●Men to Women: Add 1.5
  • ●Example: Men's 7 = Women's 8.5
• ●Women to Men: Subtract 1.5
  • ●Example: Women's 10 = Men's 8.5

Warning: Men's shoes are generally built on a "D" width (Standard), while Women's are built on a "B" width (Narrow). If you are a woman buying men's shoes, they might feel slightly wide.

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3. Width: The Forgotten Dimension

Length is only half the battle. If you have wide feet, a standard shoe will feel tight in the toe box, forcing you to "size up" and leaving you with clown shoes that are too long.

Buying Tip: If you see a shoe listed as "New Balance 990v6 (2E)", that means it is a Wide version. If you have standard feet, avoid it; your foot will slide around.

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4. Tutorial: How to Measure Your Feet at Home

Do not hold a ruler up to your foot in the air. Your foot expands when you stand on it. Follow this "Trace & Measure" method for accuracy.

What you need: A piece of paper, a pen, and a wall.

1. ●Prep: Put on the type of socks you plan to wear.
2. ●Position: Place the paper on the floor with the short edge touching a wall.
3. ●Stand: Step on the paper with your heel firmly touching the wall.
4. ●Trace: Trace the outline of your longest toe. (Note: For some people, the second toe is longer than the big toe!).
5. ●Measure: Use a ruler to measure from the edge of the paper (heel) to the mark you made (toe).
6. ●The Secret: Most modern sneaker tags (Nike/Adidas) list a "CM" or "JP" size. This is effectively your foot length in centimeters. This is the most accurate way to buy shoes.

The Magic Calculation: Take your measurement in CM and add 0.5cm for "wiggle room." This is your ideal shoe size.

🩲 Bonus Tool: Men's Clothing Sizes

Since you are updating your wardrobe, check your other sizes too:

Summary

• ●Trust the CM/JP Size: It is the only consistent metric across brands.
• ●Measure at Night: Your feet swell during the day. A shoe that fits at 9 AM might pinch at 9 PM.
• ●Check the Width: Don't squeeze a 2E foot into a D shoe.

Now that you know your true size, you can order those overseas exclusives with confidence!