ISO 19408:2023

Overview

ISO 19408:2023 - Footwear - Sizing - Vocabulary is an international standard that defines the terminology used for measuring feet and lasts and for determining shoe sizes. Published by ISO (first edition, April 2023), it replaces ISO/TS 19408:2015 and complements ISO 19952 (Footwear - Vocabulary). The standard provides precise definitions, measurement points, and multiple measurement methods for core footwear sizing concepts - supporting consistent communication across design, production and quality processes in the footwear industry.

Key topics and technical requirements

ISO 19408:2023 focuses on a comprehensive footwear sizing vocabulary and includes:

• Foot dimensions and shoe sizing

  • Definitions such as foot length, central line of foot, inside tangent, instep point, joint (ball) girth, stick (linear) width, tread width of the ball area, toe allowance, effective shoe length, design allowance, shoe size, shoe width, and grading intervals.
  • Multiple measurement methods (e.g., alternative central line definitions, instep point at 50% or 55% of foot length) to reflect practical measurement differences.
  • Guidance on measurement conditions (standing posture, barefoot or thin hosiery).

• Last dimensions

  • Terms such as last length, effective last length, bottom pattern length, feather line, heel (back) curve of last, heel height of last, heel seat, last toe height, last toe spring, tread width of the ball area of last, and long/short heel girth.
  • Definitions for technical heel height, tread and linear widths of heel, and procedures for locating measurement points on the last.

• Illustrative annex

  • Annex A (informative) provides figures showing measurement points and examples (foot length methods, tread width, central line of last bottom, etc.), supporting consistent interpretation.

Note: ISO 19408 contains no normative references and is intended as a vocabulary, not a test method.

Practical applications and users

ISO 19408:2023 is essential for organizations that require consistent footwear sizing terminology and measurement references, including:

• Footwear designers and pattern-makers (last development, fit specifications)
• Last manufacturers and technical engineers
• Quality assurance and size grading teams in footwear production
• Retailers and e‑commerce teams managing size charts and conversion tables
• Standards bodies, researchers and educators in biomechanics and ergonomics

Adopting this vocabulary improves communication across supply chains, reduces sizing errors, and supports customer fit accuracy in product development and size conversion.

Related standards

• ISO 19952 - Footwear - Vocabulary (complementary)
• ISO 19407 - referenced for shoe-size conversion tables in measurement procedures
• Work overseen by ISO/TC 137 - Footwear sizing designations and marking systems

Keywords: ISO 19408:2023, footwear sizing, vocabulary, foot measurements, last dimensions, shoe size, toe allowance, joint girth, tread width.