Half-Size Differences
US and UK systems don't always align on half sizes. Some conversions require rounding, which may affect fit for narrow or wide feet. When between sizes, consider foot width.
US to UK Shoe Size Converter
United States (US) shoe sizes are converted to United Kingdom (UK) sizes using standardized conversion charts based on ISO 9407 footwear sizing standards. The UK system uses the historical barleycorn measurement (1/3 inch per size), while US sizing evolved from the Brannock Device standard. Conversions differ between men's, women's, and children's categories due to separate scaling practices.
Each category uses different conversion offsets
Enter a size between 1 and 20
UK Size:
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Quick US to UK Reference
US 8 Men's
UK 7.5
US 9 Men's
UK 8.5
US 8 Women's
UK 6
US 10 Women's
UK 8
Men's: subtract 0.5 from US size. Women's: subtract 2 from US size. For complete charts, see below.
Understanding US to UK Conversion
The UK sizing system uses a barleycorn-based scale where each size increment represents 1/3 inch (8.46 millimeters). This historical system has been documented by the British Footwear Manufacturers Association and remains consistent across most British and Commonwealth manufacturers, including those in Australia, India, and South Africa.
US sizing differs by gender category. Men's US sizes are typically 0.5 to 1 size larger than UK equivalents (US 10 = UK 9.5). Women's US sizes are approximately 2 sizes larger than UK sizes (US 8 = UK 6). This difference stems from historical sizing practices where US women's sizing adopted a separate numerical scale that starts at a different reference point.
Children's sizing follows similar conversion patterns but uses separate scales for toddlers and youth categories. Both systems reset their numbering at different developmental stages, making direct conversion less reliable for very young children. The ISO 9407 standard provides guidelines for international harmonization, though historical regional practices persist in consumer markets.
Conversion Limitations
Width Standards
UK sizing traditionally uses descriptive width fittings (narrow, standard, wide). US sizing uses letter designations (B, D, EE) that don't directly correlate to UK width options.
Athletic Footwear
Athletic brands often use modified sizing. Nike, Adidas, and New Balance may apply different conversion standards than dress shoe manufacturers. Check brand-specific charts.
Regional Production
Shoes manufactured for UK markets may fit differently than US market products, even with identical size markings. Last shapes vary by intended market and brand origin.
These conversions are approximations based on industry standards. Actual fit depends on brand-specific sizing practices, shoe design, and individual foot characteristics. Trying footwear in person or consulting manufacturer size guides is recommended.
US to UK Size Conversion Charts
Men's US to UK Conversion
| US Size | UK Size | Foot Length (cm) |
|---|---|---|
| 7 | 6.5 | 25.0 |
| 7.5 | 7 | 25.4 |
| 8 | 7.5 | 25.9 |
| 8.5 | 8 | 26.2 |
| 9 | 8.5 | 26.7 |
| 9.5 | 9 | 27.1 |
| 10 | 9.5 | 27.6 |
| 10.5 | 10 | 28.0 |
| 11 | 10.5 | 28.4 |
| 12 | 11.5 | 29.4 |
Women's US to UK Conversion
| US Size | UK Size | Foot Length (cm) |
|---|---|---|
| 5 | 3 | 22.0 |
| 5.5 | 3.5 | 22.4 |
| 6 | 4 | 22.9 |
| 6.5 | 4.5 | 23.3 |
| 7 | 5 | 23.8 |
| 7.5 | 5.5 | 24.1 |
| 8 | 6 | 24.6 |
| 8.5 | 6.5 | 25.0 |
| 9 | 7 | 25.4 |
| 10 | 8 | 26.2 |
Complete size charts with additional sizes and children's conversions are available on the comprehensive Size Charts page.
Frequently Asked Questions
How do you convert US shoe size to UK?
For men's shoes, subtract 0.5 from the US size to get the UK size (US 9 = UK 8.5). For women's shoes, subtract 2 from the US size (US 8 = UK 6). This conversion is based on the barleycorn measurement system used in UK sizing, where each size represents 1/3 inch (8.46mm), and accounts for different starting points between the systems.
Is a US size 8 the same as UK size 8?
No, they are different. For men, US size 8 converts to approximately UK size 7.5 (foot length ~25.9 cm). For women, US size 8 converts to UK size 6. The US and UK systems evolved independently using different starting points and scaling practices, despite both systems using 1/3 inch increments for size progression.
What is US size 10 in UK?
For men, US size 10 equals UK size 9.5 (foot length approximately 27.6 cm). For women, US size 10 equals UK size 8. The conversion differs between genders because US women's sizing uses a separate numerical scale that starts at a different point than US men's sizing—a historical practice from early 20th century footwear marketing.
Are US to UK shoe size conversions exact?
Conversions are based on standardized charts from ISO 9407 and industry references, providing reliable approximations. However, brands may vary slightly in their interpretations. UK sizing uses the historical barleycorn system while US sizing evolved from the Brannock Device standard.
Why are US women's sizes so different from UK?
US women's sizing uses a separate numerical scale that starts at a different reference point than men's sizing, creating a 2-size offset from UK women's sizes. UK sizing maintains more numerical consistency between genders. This historical difference originated in early 20th century American footwear marketing and persists today.
Should I round up or down when converting US to UK?
When exact half-size equivalents don't exist, rounding depends on foot width and shoe type. For narrow feet or athletic shoes, rounding down may work better. For wider feet or closed-toe dress shoes, rounding up provides more comfortable room. When possible, try both sizes or use the foot length calculator for more accurate sizing.
Do UK and US use the same width measurements?
No. UK sizing traditionally uses descriptive width fittings (narrow, standard, wide, extra wide), while US sizing uses letter designations (B, D, E, EE, etc.). The systems don't directly correlate. UK standard width is approximately equivalent to US D width for men or US B width for women, but availability varies by brand and style.
Disclaimer
This calculator provides size conversions based on widely accepted industry standards and the ISO 9407 footwear sizing standard. Conversions are approximations and do not guarantee accurate fit.
Actual shoe fit depends on multiple factors including foot shape, shoe width, brand-specific sizing practices, and manufacturing variations. The foot length calculator provides more accurate sizing by using direct measurements rather than system-to-system conversion.
No warranty or guarantee is provided regarding conversion accuracy. Users are encouraged to consult brand-specific size charts and try footwear when possible. See the full disclaimer page for additional information.