Shoe size by manufacturer: why your size 10 isn't the same brand to brand

Two shoes labelled “US 10” from different brands can differ by 5-10 mm in actual interior length, plus differences in width, toe-box height, and arch placement. The shoe sizing system measures thelast (the wooden form the shoe is built on), not the foot, and every manufacturer has their own last geometry. This guide explains what to expect from the most common brands.

Why brands disagree

Three sources of variation:

1. Last geometry. The wooden or digitally-modelled form the shoe is constructed around. Width, instep height, toe-box volume, and heel-to-ball ratio all vary. Two shoes built on different lasts at the same nominal size feel different.
2. Construction allowances. A goodyear-welt dress shoe has a stiff structure that holds the last shape rigidly. A running shoe with knit upper stretches with use; brands account for this differently.
3. Geography.European dress brands tend to run narrow. American athletic brands target a wider average foot. Japanese brands cater to typically narrower feet still. Even within US brands, “D” width standards aren’t quite the same.

The brands, roughly catalogued

Athletic — typically run true or slightly small

• Nike. Generally true to size for casual; running models often run a half-size small with a narrow last. The Pegasus, Vaporfly, and Alphafly all skew narrow.
• Adidas. True to size in lifestyle (Stan Smith, Samba) and slightly large in running (Ultraboost, Adios).
• New Balance. True to size, often with width options (D, 2E, 4E). The best mass-market option for wide feet.
• Asics. True to size in the GT and Cumulus; slightly narrow in the Gel-Kayano.
• Brooks. Slightly large; many runners size down half. Wide-width versions widely available.
• Hoka. True to size in most models; Clifton and Bondi run wide-ish for high-volume feet.
• On. Slightly small and narrow; many size up half.

Dress shoes — varies wildly

• Allen Edmonds (US). Generally a half-size larger than athletic shoes. The Park Avenue at “10D” fits like a Nike 10.5D.
• Alden (US). Built on multiple lasts (Plaza, Barrie, Aberdeen, etc.) that fit very differently. The Barrie last runs about a half-size large with a wide toe box.
• Crockett & Jones (UK). True to UK sizing, which runs about a half-size smaller than US. UK 9.5 fits a US 10 foot.
• Edward Green (UK). Multiple lasts; the 202 fits half a size large with extra toe room, the 82 is narrower.
• Salvatore Ferragamo (IT). Italian sizing runs narrow; many US buyers go a half to full size up.
• John Lobb (UK). Bespoke or high-end ready-to-wear; sizing varies per last, fit is closer than off-the-shelf.

Boots

• Red Wing. Heritage boots (Iron Ranger, 875) typically run a half-size large because they’re built on an old wide last.
• Wolverine 1000 Mile. Similar — half-size large, narrow last.
• Dr. Martens. Notoriously inconsistent. Many buyers size down a full size; women’s buyers often pick men’s sizes for better-fitting toe boxes.
• Blundstone. Australian sizing runs a half-size larger than UK; AU 8 = UK 7.5 = US 9 (men’s).

How to actually buy across brands

1. Measure your foot in millimetres. Heel to longest toe, weight on the foot, end of day (feet are longest in the evening). Both feet — the larger one governs.
2. Find the brand’s own size chart.Most reputable brands publish foot-length-to-size tables. Use the brand’s chart, not a generic conversion.
3. Read width carefully.US D is medium for men; US B is medium for women. 2E is wide; 4E is extra wide; B (men) is narrow. UK and EU sizing don’t encode width as numerically; you may need to specifically ask.
4. Check return policy before buying online.Zappos, REI, Allen Edmonds (1 year), and Nordstrom all have generous return policies that make experimental cross-brand sizing painless. Brand DTC sites vary.
5. Visit a Brannock-equipped store at least once. The Brannock device measures length, width, and heel-to-ball — a baseline that lets you interpret brand-specific charts intelligently.

The cross-region cheat sheet

Standardised conversions to use as a starting point (always check brand chart for the final pick):

Use our shoe size converter for any direction, or the US vs EU shoe size comparison for the full history of how the systems diverged.

Sources: ISO 9407 (Mondopoint); Allen Edmonds last specifications (publicly available); Brannock Device documentation; Carlos Santos, The Shoe Snob (blog) reference fit notes.