Size Conversion Methodology

At ConvertSizes, accuracy is our priority. This page explains how we research, calculate, and maintain our size conversion charts.

Data Sources

Our conversion data is compiled from multiple authoritative sources:

• International sizing standards (ISO, EN)
• Official brand sizing guides
• Industry association guidelines
• Government measurement standards

Shoe Size Conversions

Shoe sizes are based on foot length measurements. Different regions use different formulas:

• US sizes - Based on the Brannock device, with men's and women's scales offset by approximately 1.5 sizes
• UK sizes - Similar to US but with different starting point; men's and women's use the same scale
• EU sizes (Paris points) - Each size equals 2/3 cm (6.67mm); unisex scale
• CM/Mondopoint - Direct foot length measurement in centimeters

Clothing Size Conversions

Clothing sizes vary more significantly between brands and regions:

• US sizes - Numeric (0-16+) or letter (XS-XXL)
• UK sizes - Numeric, typically 4 sizes larger than US
• EU sizes - Numeric, based on body measurements in centimeters
• International - Letter sizes (XS, S, M, L, XL, XXL)

We provide general conversion guidelines, but recommend checking specific brand size charts for the most accurate fit.

Ring Size Conversions

Ring sizes are based on the inner circumference or diameter of the ring:

• US sizes - Numbered scale starting from size 1
• UK sizes - Alphabetical scale (A-Z)
• ISO (mm) - Inner circumference in millimeters

Handling Variations

Size conversions are not always exact. We handle variations by:

• Showing the closest equivalent when exact matches don't exist
• Noting when a size falls between two standard sizes
• Providing measurement ranges rather than single values where appropriate

Data Quality

We maintain data quality through:

• Regular review of conversion tables
• Cross-referencing multiple sources
• User feedback integration
• Periodic audits against official standards

Limitations

Please note that:

• Brand sizing can vary significantly from standard charts
• Vintage or specialty items may use different sizing
• Our charts provide general guidance, not guaranteed fit
• When in doubt, measure and consult brand-specific charts

Report an Issue

Found an inaccuracy? Please contact us with details and we'll investigate promptly.