Sizing Methodology
Size labels are not universal measurements. Sizemapped separates physical measurements from label-to-label approximations.
Measurements first
For body sizing, use physical measurements whenever a verified measurement chart exists. A printed shoe-size marking such as JP/CM is not automatically the length of a wearer’s foot, even though it uses centimeter-style units; the adult shoe label reference must not be used as a heel-to-toe conversion table.
Conversions are approximate
Generic US, UK, EU, and other label conversions represent common equivalences. A brand may publish a different mapping because of its last, pattern, grading, fit preference, or manufacturing tolerances.
When official charts disagree
Sizemapped compares standards and multiple manufacturer charts where practical. If reputable charts place the same body measurement in different retail labels, the site uses a range or marks the result as brand-dependent instead of averaging those labels into a false exact value.
Reference principles
For footwear, ISO 19407:2023 supports measurement-led size guidance, but Sizemapped’s shared adult US/UK/EU/JP/CM table currently shows approximate printed-label correspondences, not measured heel-to-toe body-length values. To choose a shoe using measured foot length, consult the specific manufacturer’s separate Foot Length or Heel-to-toe chart.
Central data, shared corrections
Repeated sizing pages are generated from shared structured data. When a source mapping is reviewed or corrected, the related pages can be updated together rather than drifting apart.
What to do when fit matters
Use the relevant brand or manufacturer chart when available and compare it with your measurement. Sizemapped is a practical reference, not a substitute for product-specific fitting information.
How external references are used
Sizemapped uses standards and manufacturer charts to check the method behind a conversion, not to imply that one brand chart is a universal standard. For footwear, ISO 19407:2023 supports using foot length as the common basis for comparing major sizing systems and explicitly treats conversion tables as guidance.
Manufacturer charts are used as spot checks rather than one universal standard. Nike distinguishes measured foot length from the CM label printed on a shoe box; adidas publishes separate heel-to-toe and JP size-label rows. That distinction means Sizemapped’s shared JP/CM label column must not be interpreted as physical foot length or used to calculate inches of foot length.
How this guidance is checked
These sources support the measurement method and help check real-world variation. They are not presented as one universal brand-size table.
- ISO 19407:2023 — Footwear — Sizing — Conversion of sizing systems — International Organization for Standardization (ISO). Measurement-first footwear methodology and the limitation that cross-system conversions are guidance rather than guaranteed fit.
- ISO 8559-2:2025 — Size designation of clothes — Primary and secondary dimension indicators — International Organization for Standardization (ISO). Clothing methodology: size designation should be based on defined body measurements rather than assuming universal retail labels.
- ISO 8559-3:2018 — Methodology for body measurement tables and intervals — International Organization for Standardization (ISO). Clothing methodology: body measurement tables are population- and interval-based rather than one universal brand-independent chart.
- Men's Footwear Size Chart — Nike. Manufacturer cross-check showing that foot length, labeled CM values, width, and brand-specific sizing conventions are distinct concepts.
- Footwear Size Guide — adidas. Manufacturer cross-check across heel-to-toe length and US, UK, EU, and Japan-labeled footwear sizes.