Transparency Record

Data Sources & Verification

All shoe size conversions and millimeter measurements are verified against authoritative primary sources.

Dataset Version: 2026-09-10

Our Verification Protocol & Provisional Status:

Before any row in our dataset is labeled VERIFIED, it must be cross-referenced against at least three independent primary brand size charts with matching measured shoe lasts. In accordance with strict data integrity, all rows in the current dataset are designated REQUIRES_VERIFICATION (provisional) until multi-brand physical audits are completed.

We never present unverified data as verified facts. Sizing guidelines are provided for approximate fitting comparison only.

Nike Kids' Footwear Size Guide

Accessed: 2026-09-10

Official Nike heel-to-toe foot length to US (C/Y), UK, and EU size specifications.

Methodology Note: Nike measures heel-to-toe length. Transition from 13.5C to 1Y occurs at ~19.5-20.0 cm.

View Primary Source

New Balance Kids Size Guide

Accessed: 2026-09-10

Standard US, UK, EU, and cm conversion charts across infant, preschool, and grade school footwear.

Methodology Note: Corroborates 1/3 inch (8.46 mm) size progression and UK = US - 0.5 to 1.0 sizing.

View Primary Source

Clarks UK Children's Fitting Guide

Accessed: 2026-09-10

Pediatric foot measurement standard established by Clarks UK, providing growing-room allowances.

Methodology Note: Emphasizes the standard 10-14 mm (~12 mm) toe room allowance for natural gait and foot expansion.

View Primary Source

Skechers Kids Footwear Sizing

Accessed: 2026-09-10

Children's footwear size chart categorized across Toddler, Little Kid, and Big Kid age bands.

Methodology Note: Cross-checked for C/Y classification boundaries and EU size alignment.

View Primary Source

BlitzResults International Kids Shoe Size System

Accessed: 2026-09-10

Authoritative consolidated international sizing comparison covering US, UK, EU, cm, and inches.

Methodology Note: Used as secondary reference for cross-system comparisons.

View Primary Source

Pediatric Foot Anthropometry & Growth Distribution Studies (Müller et al., 2012)

Accessed: 2026-09-10

Observational pediatric foot morphology study (Müller et al., Gait & Posture 2012) tracking static child foot length in 7,788 children aged 1–13 years.

Methodology Note: Used as provisional baseline for population typical age-based foot length percentiles (1–12 years). Replaces historical non-foot CDC references.

View Primary Source