Methodology

How we collect and verify sizing data

Sources

• ISO 9407 (shoe sizing / Mondopoint) and ISO 8559 (garment measurement).
• EN 13402 for European clothing size labeling.
• Each brand's currently published size chart, verified quarterly.
• Retail data from published product tags in EU, US, UK, JP and KR markets.

Reconciliation

When brands publish charts that disagree with the standard (a common case for lifestyle shoes), we publish the standard number and note the brand's deviation in the brand guide. This keeps the general converter reliable while preserving accurate per-brand advice.

Rounding

All conversions between metric (EU, JP) and imperial (US, UK) systems involve rounding — the increments do not align cleanly. Where a size falls between two values we round to the more conservative (smaller) size, matching most brands' published guidance.

Fit notes

Fit notes ("runs 0.5 large", "narrow midfoot") are aggregated from brand-published guidance, retail store measurement data, and independent review consensus. When brand and review data disagree, we note both.

Limitations

Sizing charts describe average feet and average bodies. They cannot account for individual foot volume, arch height, or personal preference for looseness. Always confirm fit with the retailer's own chart before purchase.