Sources & Verification Log
Every conversion on this site traces back to a recorded source. If a source is missing, the build fails — that is enforced by code, not discipline.
Current sources
| Source | Kind | URL | Accessed | Used for |
|---|---|---|---|---|
| Shoe size — system definitions and conversion tables (documents ISO 19407 relations) | secondary-reference | https://en.wikipedia.org/wiki/Shoe_size | 2026-10-09 | 430 entries · 1 crosswalk |
| BlitzResults shoe size charts (independent cross-check) | secondary-reference | https://www.blitzresults.com/en/shoe-size/ | 2026-10-09 | verification / cross-check only |
| Flexi — guía de tallas oficial (Mexican footwear manufacturer) | manufacturer | https://somos.flexi.com.mx/guia-de-tallas | 2026-10-11 | 23 entries · 46 crosswalks |
| Liverpool México — guía de tallas de calzado (Mexican retailer) | retailer | https://assetspwa.liverpool.com.mx/guia-de-tallas/calzado.html | 2026-10-11 | verification / cross-check only |
| Nike — official Kids' Footwear Size Chart (manufacturer) | manufacturer | https://www.nike.com/size-fit/kids-footwear | 2026-10-11 | 54 crosswalks · verifies: EU Kids |
| Williams Shoes — size guide (Australian footwear retailer) | retailer | https://www.williamsshoes.com.au/size-guide | 2026-10-12 | verification / cross-check only |
| Target Australia — shoe size charts, men's + women's (Australian retailer) | retailer | https://www.target.com.au/size-chart/menshoe | 2026-10-12 | verification / cross-check only |
| ISO 19407:2023 — official record + authorized preview verification | standard | https://www.iso.org/standard/83106.html Verification material: preview used | 2026-10-12 | verifies: US Men, US Women, UK, EU (Paris point) |
| Nike — official adult footwear size charts, men's + women's (manufacturer) | manufacturer | https://www.nike.com/size-fit/mens-footwear | 2026-10-12 | verifies: US Men, US Women, UK, EU (Paris point) |
| ASICS — official regional size guide, adult + kids (manufacturer) | manufacturer | https://me.asics.com/en-om/shoe-size-guide | 2026-10-13 | verifies: US Men, US Women, UK, EU (Paris point), EU Kids |
| PUMA — official EU size guide, kids shoes (manufacturer) | manufacturer | https://eu.puma.com/de/en/help/size-guide | 2026-10-13 | verifies: EU Kids |
| ISO 9407:2019 — official record + authorized preview verification | standard | https://www.iso.org/standard/71594.html Verification material: preview used | 2026-10-13 | verifies: Mondopoint (mm) |
| Burton — official size charts + boot sizing guides (manufacturer) | manufacturer | https://www.burton.com/en-us/pages/size-charts | 2026-10-13 | verifies: Mondopoint (mm) |
| Rossignol — official alpine ski boot guide (manufacturer) | manufacturer | https://www.rossignol.com/us-en/alpine-ski-boots-material-guide.html | 2026-10-13 | verifies: Mondopoint (mm) |
Verification notes
Shoe size — system definitions and conversion tables (documents ISO 19407 relations): Secondary reference documenting the scale relations (UK=3L-23, US men=UK+1, US women=common scale, EU=1.5cm+2, kids scales; AU men=UK, AU women=US women as market convention). Not itself a standards document. Direct verification against ISO 19407:2023 is still pending — tracked by the source-verification matrix and re-verification cadence.
BlitzResults shoe size charts (independent cross-check): Independent reference site. Agrees with the documented relations within one half size on US/UK/EU adult boundaries; disagreements are the reason all labeled-size conversions carry approx flags. Cross-check only — backs no dataset rows directly.
Flexi — guía de tallas oficial (Mexican footwear manufacturer): Primary source for the Mexico system: centimetre-marked retail sizes. Men (Caballero) MX 25–31 ↔ US men 7–13; Women (Dama) MX 22–27 ↔ US women 5–10; kids tables also cm-marked (not yet implemented).
Liverpool México — guía de tallas de calzado (Mexican retailer): Cross-check for Mexico: agrees with Flexi on every overlapping row (MX 22–30 men and women). Backs no dataset rows directly.
Nike — official Kids' Footwear Size Chart (manufacturer): Primary source for the US youth scale: three tables (Babies & Toddlers 1C-10C, Little Kids 8C-3Y, Big Kids 1Y-7Y) with US/UK/EU/CM and explicit foot-length rows. Backs the 52 Y-scale crosswalks (Y = men's number; women's = Y + 1.5) and the golden foot-length anchors (1Y/3Y/7Y). Corroborated by Stride Rite rows within ~2 mm (via Kohl's-hosted chart, 2026-10-11). Known chart quirks (7Y->UK 6 sequence break, Kohl's 1Y->UK 1 replication error) documented in docs/kids-sizing-verification.md §6.
Williams Shoes — size guide (Australian footwear retailer): Primary Australian-market source for the AU convention: states women's sizes are 'based on the US size scale' (AU = US) and men's sizes use the UK scale (AU = UK), with full conversion rows and foot-length ranges. Kids tables are presented directly in US/UK/EU. Backs the equivalentTo metadata on au-m/au-w only — NOT the foot-length grids (those keep the wiki-documented relations).
Target Australia — shoe size charts, men's + women's (Australian retailer): Australian-market cross-check for BOTH conventions: the men's chart (url above) prints a single combined 'AU/UK' column (e.g. AU/UK 7 = US 8 = EU 40 = 254 mm) confirming AU men = UK; the women's chart (https://www.target.com.au/size-chart/wmnshoe) prints a combined 'AU/US' column (e.g. AU/US 5 = UK 3 = EU 36 = 220 mm) confirming AU women = US women. Backs no rows and no grid — numbering-convention evidence only.
ISO 19407:2023 — official record + authorized preview verification: `url` is the official ISO catalog record (standard identity, edition, scope/existence). `verificationUrl` is the exact authorized distributor (iTeh) public preview/sample used for the sampled UK/EU row checks — scope, clause 4.2 conversion formulas, Table 1 rows 210-322 mm, Table 2 recommended markings. The full standard is PAYWALLED: only the visible preview content was verified, nothing beyond it is claimed, no copyrighted tables are reproduced, and this source backs NO dataset rows or crosswalks. Verification evidence for the adult UK/EU technical grids and US/UK relations only (System.verifiedAgainst).
Nike — official adult footwear size charts, men's + women's (manufacturer): Official Nike adult size charts (men's page above; women's at https://www.nike.com/size-fit/womens-footwear; corroborated by nike.ae snippets). Verification evidence only — backs NO dataset rows or crosswalks. Establishes the retail US men↔UK label relation (US = UK +1, with the documented US 6 → UK 5.5 small-size exception) and the men↔women +1.5 common retail convention printed on every row of the combined chart. Recommended-fit foot lengths sit ~+4 mm above the neutral grid (fit allowance). One inconsistent table variant/extraction was observed and excluded — see docs/adult-sizing-verification.md §3.
ASICS — official regional size guide, adult + kids (manufacturer): Official ASICS regional size guide (men's/unisex + dedicated women's + KIDS tables, half sizes, UK/EU/CM/US). Verification evidence only — backs NO dataset rows or crosswalks. Men's/unisex table confirms US = UK +1 on every row and corroborates the men↔women relationship via shared UK anchors; the DEDICATED women's table numbers women→UK closer to −2 (brand convention variance, not a universal equivalence). CM values sit several mm above the neutral grids — cause not established (fit allowance, chart convention or measurement semantics). Adult EU labels run +0.5-1 above the technical grid. Kids table (checked 2026-10-13, docs/eu-kids-36-40-verification.md §4): youth EU labels run 0 to +0.5 ABOVE the neutral pairs — brand label variance, not grid corroboration; youth UK = Y − 1 consistently (4Y→UK 3 … 7Y→UK 6, corroborating Nike’s 7Y→UK 6 row). NOTE: originally retrieved from asics.com/gb (2026-10-12, now 404 after ASICS reorganized); re-checked 2026-10-13 at me.asics.com/en-om — the regional guides carry one shared table (adult tables identical to the GB original).
PUMA — official EU size guide, kids shoes (manufacturer): Official PUMA EU size guide, 'Kids shoes' table (EU | UK | US; NO foot-length column — label evidence only). Youth EU labels (checked 2026-10-13, docs/eu-kids-36-40-verification.md §5): 4Y=EU 35.5 … 7Y=EU 39 — the LOWEST of the three manufacturers, falling inside the neutral Paris-point pairs at every row while Nike (+0.25–+0.75) and ASICS (0–+0.5) label above; no universal Y→EU mapping exists. Verification evidence only — backs NO dataset rows or crosswalks.
ISO 9407:2019 — official record + authorized preview verification: `url` is the official ISO catalog record (edition 2, 2019-06, ISO/TC 137; supersedes ISO 9407:1991). `verificationUrl` is the exact authorized distributor (iTeh) public preview/sample used for the Mondopoint verification — clause 4.2: 'The size designation of the footwear is based on the measured length of the foot, expressed in millimetres, for which the footwear is intended.' The full designation can also encode foot WIDTH in millimetres (preview shows '240/95'-style examples; full width rules are paywalled). This site's converter uses the LENGTH dimension only. Backs NO dataset rows or crosswalks — verification evidence for the mondopoint system only (System.verifiedAgainst); does not back manufacturer-specific fit behaviour.
Burton — official size charts + boot sizing guides (manufacturer): Official Burton size charts (url above) print a dedicated Mondo column for men's/women's snowboard boots listing whole AND half sizes (24, 24.5, 25, 25.5, 26, 26.5, 27, 27.5 ...) alongside US/EU/UK; Burton's sizing guides (https://www.burton.com/en-us/blogs/the-burton-blog/sizing-kids-snowboard-boots) state Mondo 'is essentially the length of your foot in centimeters'. Verification evidence only — backs NO dataset rows. Corroborates retail use of Mondopoint labels (5 mm steps incl. halves) = foot length in cm/mm.
Rossignol — official alpine ski boot guide (manufacturer): Rossignol's official alpine ski boot guide states that ski-boot size in Mondo Point (MPS) corresponds to the measured foot length in centimetres; example given: a 26.5 cm foot → a 26.5 Mondo Point boot. Verification evidence only — backs NO dataset rows. Independent manufacturer corroboration that Mondopoint labels = foot length in cm/mm.
Changelog
- 2026-10-13 — dataset 1.0.0: initial dataset. 453 size entries across 13 systems, generated from documented scale relations; golden-value checks against published tables; cross-checked against one independent reference chart. Adult US/UK/EU grids and Mondopoint were subsequently verified against ISO 19407:2023 / ISO 9407:2019 (authorized previews) and official manufacturer charts — see the verification notes above and the source-verification matrix in the repo.
- 2026-10-11 — Mexico system corrected: replaced the derived 3.5–14.5 grid with centimetre-marked retail sizes (men 25–31, women 22–27) from the official Flexi size guide (manufacturer), cross-checked row-for-row against Liverpool Mexico (retailer). Kids' Mexican sizes are intentionally not yet supported. No other system's data changed.
Re-verification cadence
Sources are re-checked every six months. Entries that fail re-verification are flagged or withdrawn — never silently changed. Brand-specific tables (Phase 3) will be published only from official manufacturer charts, each displayed with a "Source: <brand> official chart · Last verified: <date>" line on the page itself.