Understanding Shoe Size Conversion: A Comprehensive Guide
Shoe size conversion can be confusing with different sizing systems used around the world. This comprehensive guide explains how to convert between US, EU, UK, and other sizing systems, why sizes vary by brand, and how to ensure the perfect fit when shopping for shoes internationally.
Why Shoe Size Conversion Matters
With global online shopping and international travel more common than ever, understanding shoe size conversion is essential for:
- Online shopping: Buying shoes from international retailers
- Travel: Purchasing shoes while abroad
- Gift-giving: Buying shoes for friends or family in other countries
- Brand variations: Understanding how different brands fit
- Vintage shopping: Converting older sizing systems
Did You Know?
The modern shoe sizing system originated in England in the 14th century when King Edward II declared that the diameter of one barleycorn (about 1/3 inch) would represent one full shoe size. This system evolved into the UK sizing system still used today.
Major Shoe Sizing Systems Explained
| System | Used In | Base Measurement | Notes |
|---|---|---|---|
| US | United States, Canada | Barleycorns (1/3 inch per size) | Different scales for men, women, and children |
| UK | United Kingdom, Ireland, Australia, New Zealand | Barleycorns (1/3 inch per size) | Starts at 0 for children's sizes |
| EU | Europe, most of Asia, South America | Paris point (2/3 cm per size) | Unisex sizing with same scale for men and women |
| JP | Japan | Centimeters | Actual foot length in cm |
Standard Conversion Tables
Men's Shoe Size Conversion
// Men's Standard Size Conversion
const mensSizes = {
US: [6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13],
UK: [5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12],
EU: [39, 40, 40.5, 41, 42, 42.5, 43, 43.5, 44, 44.5, 45, 45.5, 46, 46.5, 47],
CM: [24.1, 24.6, 25.1, 25.4, 25.9, 26.2, 26.7, 27.1, 27.6, 27.9, 28.3, 28.6, 29.1, 29.4, 29.8],
IN: [9.5, 9.7, 9.9, 10, 10.2, 10.3, 10.5, 10.7, 10.9, 11, 11.1, 11.3, 11.5, 11.6, 11.7]
};Women's Shoe Size Conversion
// Women's Standard Size Conversion
const womensSizes = {
US: [5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12],
UK: [2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5],
EU: [35.5, 36, 36.5, 37, 37.5, 38, 38.5, 39, 39.5, 40, 40.5, 41, 41.5, 42, 42.5],
CM: [21.6, 22.2, 22.5, 23, 23.5, 23.8, 24.1, 24.6, 25.1, 25.4, 25.9, 26.2, 26.7, 27.1, 27.6],
IN: [8.5, 8.7, 8.9, 9.1, 9.3, 9.4, 9.5, 9.7, 9.9, 10, 10.2, 10.3, 10.5, 10.7, 10.9]
};Kids' Shoe Size Conversion
// Kids' Standard Size Conversion
const kidsSizes = {
US: [10.5, 11, 11.5, 12, 12.5, 13, 13.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6],
UK: [9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5],
EU: [27, 28, 29, 30, 30.5, 31, 31.5, 32, 33, 33.5, 34, 35, 35.5, 36, 36.5, 37, 37.5, 38],
CM: [16.8, 17.1, 17.5, 17.8, 18.1, 18.4, 18.7, 19.1, 19.4, 19.7, 20, 20.3, 20.6, 21, 21.3, 21.6, 22, 22.4],
IN: [6.6, 6.7, 6.9, 7, 7.1, 7.2, 7.4, 7.5, 7.6, 7.8, 7.9, 8, 8.1, 8.3, 8.4, 8.5, 8.7, 8.8]
};Pro Tip:
When converting between US and UK sizes, remember that UK sizes are typically 1-1.5 sizes smaller than US sizes for adults (e.g., US men's 9 = UK 8). For EU sizes, subtract 31-33 from the EU size to get approximate US men's sizes (e.g., EU 42 - 33 = US 9).
Brand-Specific Variations
Many shoe brands have their own sizing quirks that deviate from standard conversions:
Nike
- Runs small by about 0.5 size
- Narrow fit in many styles
- Basketball shoes often run large
Adidas
- Generally true to size
- Wider toe box than Nike
- Some models run large (e.g., Ultraboost)
Birkenstock
- EU sizes are accurate
- US conversion often runs large
- Wide footbed requires adjustment
Converse
- Runs large by about 0.5-1 size
- Narrow fit in standard models
- Consider sizing down
How to Measure Your Foot Accurately
For the most accurate size conversion , measure your foot properly:
- Time it right: Measure feet at the end of the day when they're largest
- Wear socks: Use the type you'll wear with the shoes
- Stand on paper: Place a sheet of paper on a hard floor
- Trace your foot: Have someone trace your foot while standing straight
- Measure length: Measure from heel to longest toe in cm or inches
- Measure width: Measure the widest part of your foot
- Use larger foot: Always size to your larger foot
// Foot Measurement Best Practices
const footMeasurement = {
time: "Evening when feet are largest",
socks: "Wear intended sock thickness",
surface: "Hard, flat surface",
position: "Stand straight with weight evenly distributed",
tools: "Ruler or measuring tape, paper, pencil",
measurements: [
"Length: Heel to longest toe",
"Width: Widest part of foot",
"Arch length: Heel to ball of foot"
],
sizing: "Use measurements of larger foot"
};Common Conversion Mistakes to Avoid
Assuming Unisex Sizing
US and UK sizes are gender-specific (men's 8 ≠ women's 8). Always specify gender when converting.
Ignoring Half Sizes
Rounding half sizes can lead to poor fit. A US men's 9.5 converts to UK 8.5, not 8 or 9.
Overlooking Width
Width designations (D, E, EE) don't convert directly between systems. Consider separate width measurements.
Brand Generalizations
Assuming all brands fit the same. Always check brand-specific sizing when available.
When to Size Up or Down
Consider these factors when deciding between sizes:
- Activity: Running shoes often need extra space (1/2 size up)
- Material: Leather stretches, synthetics don't
- Toe shape: Pointed toes may require sizing up
- Season: Feet swell in summer/hot weather
- Socks: Thick socks need more room
- Orthotics: Custom inserts may require more volume
Final Tip:
When shopping internationally, always check the retailer's return policy. Even with accurate conversions, trying shoes is the best way to ensure proper fit. Many online retailers now offer free returns for sizing issues.
Understanding shoe size conversion eliminates guesswork when shopping for footwear across different sizing systems. By using accurate conversion tools, considering brand variations, and measuring your feet properly, you can confidently find shoes that fit perfectly, no matter where they're made or sold.