How We Calculate Shoe Sizes
The adult technical reference uses ISO 19407:2023 §4.2, rounded to the nearest half size. Its US women’s convention is one size above US men’s; manufacturer tables use different offsets. A label-derived foot length is an estimate, not a measurement.
Technical reference; manufacturer labels may differ.
The adult technical reference uses ISO 19407:2023 §4.2, rounded to the nearest half size. Its US women’s convention is one size above US men’s; manufacturer tables use different offsets. A label-derived foot length is an estimate, not a measurement.
Applies to
Size labels and measured foot length are different quantities. A chart does not establish the fit of every model.
Official charts support the transcribed size labels. Product pages support advice only for the stated model, version and market. We do not publish unsupported review counts, fit distributions or calibrated fit probabilities.
Editorial review
“Source checked” records when the cited page was read. “Editorial review” records a change to our explanation. Neither is reset during a build, and no automatic monthly verification schedule is claimed.
ISO 19407:2023 §4.2
Technical reference; manufacturer labels may differ.
- UK ≈ mm / 8.47 − 23
- US ♂ ≈ mm / 8.47 − 22
- US ♀ ≈ mm / 8.47 − 21
- EU ≈ mm / 6.67 + 2
- cm = mm / 10
Official source: ISO 19407:2023 · Source checked: 2026-09-05
US 9 — Published size chart
Size labels and measured foot length are different quantities. A chart does not establish the fit of every model.
| Official source | EU | US women | Foot length (mm) | CM / JP label |
|---|---|---|---|---|
| Nike | 42.5 | 10.5 | 262 | 27 |
| Adidas | 42 2/3 | 10 | 263 | 27 |
| Converse | 42.5 | 11 | 275 | — |
| New Balance | 42.5 | 10.5 | — | 27 |
Published size chart
- Adidas — Men and women footwear chart; Shoe size chart → cm → Heel-toe / US - Men / US - Women / EU / UK / JP · Source market: US · Source checked:
- ASICS — Men's footwear; Shoe Size Guide → Men's → US / EU / CM / UK · Source market: Singapore · Source checked:
- Brooks — Men's running footwear; Men's Shoe Size Chart → US / UK / Europe · Source market: US · Source checked:
- Converse — Chuck Taylor All Star and Chuck 70 only; Chuck Taylor All Star Size Chart → cm; Includes Chuck Taylor All Star & Chuck 70 · Source market: US · Source checked:
- Hoka — Men's regular footwear chart; Sizing Information → Men → Footwear → Regular → Measurements cm; Foot Length (CM), US, UK, Europe, Japan (CM); How To Measure. · Source market: US · Source checked:
- Hoka — Women's regular footwear chart; Sizing Information → Women → Footwear → Regular → Measurements cm; Foot Length (CM), US, UK, Europe, Japan (CM); How To Measure. · Source market: US · Source checked:
- New Balance — Men's/unisex footwear; Size & Width Guide → Men's/Unisex → length chart · Source market: US · Source checked:
- Nike — Men's footwear; women's labels refer to the same men's/unisex chart; Size Chart → cm; US - Men, US - Women, UK, CM / JP, EU, Foot Length (cm) · Source market: US · Source checked:
- Nike — Women's footwear; cross-labels in Nike's women's chart; Size Chart → US - Women, US - Men, US - Kids, UK, CM / JP, EU; Metric → Foot Length (cm). Public chart payload foot_length_cm in sizeCharts.data. · Source market: US · Source checked:
- Puma — Men's shoes; International Size Conversions → Men's shoes → DE / UK / US · Source market: GB / Europe · Source checked:
- Reebok — Unisex shoes; general US size guide; Unisex Shoes Size Guide → U.S. Men / U.S. Women / Heel-Toe Measurement (in) · Source market: US · Source checked:
- Salomon — Men's footwear; Men's Footwear → cm → FOOT LENGTH / UK / EUR / US / JP · Source market: GB · Source checked:
- Vans — Unisex shoes; Unisex Shoes → US Men / US Women / UK / EU / JP · Source market: US · Source checked:
Model guides
- Adidas NMD_R1
- Official source — NMD_R1 normal size and sock-like construction · Source checked: 2026-09-05
- Adidas Stan Smith
- Official source — Adult/unisex sizing; normal size; upper-material differences · Source checked: 2026-09-05
- Adidas Ultraboost 1.0
- Official source — Size guidance: runs small; half size up · Source checked: 2026-09-05
- Official source — Size guidance: true to size; usual size · Source checked: 2026-09-05
- Brooks Ghost 18
- Official source — Ghost 18 → SELECT WIDTH: Narrow (1B), Medium (1D), Wide (2E), Extra Wide (4E); PRODUCT DETAILS → BEST FOR: Road running. · Source checked: 2026-09-30
- Converse Chuck Taylor All Star Canvas
- Official source — Size Guide: runs large, half size down; SKU A15958F; canvas upper · Source checked: 2026-09-05
- New Balance 574 Core
- Official source — Runs small: consider ordering up; D/2E/4E widths; style ML574EVB · Source checked: 2026-09-05
- New Balance Made in USA 990v6
- Official source — Fit guidance; widths 2A/B/D/2E/4E/6E; style M990NV6 · Source checked: 2026-09-05
- Nike Air Force 1
- Official source — Air Force 1 sizing; wide feet; upper material and editions · Source checked: 2026-09-05
- Salomon Speedcross 6 Wide
- Official source — Men’s trail running; Wide/EE fit; product L41744000 · Source checked: 2026-09-05
- Salomon XT-6
- Official source — Unisex sneaker/Sportstyle; product L41252900; Quicklace · Source checked: 2026-09-05
- Vans Old Skool
- Official source — Lifestyle / suede-canvas; style VN000E9TY28; padded collar and lace closure · Source checked: 2026-09-05
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