Sources

Shoes (adult)

• Nike men's and women's footwear size charts (US, UK, EU, JP label), as published by Nike and its retailers
• Nike men's foot-length chart in inches and cm (Kohl's Nike chart)
• adidas men's and women's shoe size charts (EU in thirds)
• RunRepeat comparison of 40+ brand shoe charts (adidas vs Nike)
• ISO 9407:2019 Footwear sizing, Mondopoint system of sizing and marking

Shoes (kids) and widths

• Nike kids' footwear chart (5C–7Y, foot length in cm) and infant chart
• Nike width size chart (N to XXW)

Bras

• Wacoal International Size Guide: band and cup conversions for UK, EU, FR, AU/NZ, US, JP
• Panache fitting guidance on UK band and cup sizing

Clothing

• Princess Highway women's size guide: letter/AU/UK/US/IT/JP with bust, waist, hip in cm
• Wacoal international dress sizes (UK/EU/FR)
• Croft & Barrow men's tops chart (Kohl's): neck, chest, waist
• Nordstrom denim size note (waist 23–33 to US 000–16)
• Blitzresults jeans size charts (men's waist, inseam by height)
• Carter's baby size chart (preemie–24M) and OshKosh B'gosh toddler and kids' chart

Accessories

• ISO 8653 ring sizes (inside circumference in mm) and the standard US ring diameter formula
• New Era 59FIFTY fitted hat size chart
• EN 420:2003 Table 2 hand sizes (now EN ISO 21420:2020) and COFRA glove marking
• The British Belt Company: belt size = waist + 2 inches
• Darn Tough men's/unisex sock size chart
• Apple Watch band listings: S/M fits 130–180 mm, M/L fits 150–200 mm

How we handle disagreement

Brands disagree, sometimes by a full size. Where two respected charts differ, the tool shows the one named on that page and notes the other (for example, Nike's EU 42.5 against adidas's EU 42 ⅔ for a US men's 9). Where a value is calculated rather than listed (ring sizes, collar centimetres, EU children's heights), the page shows the formula.

Found a mismatch with a brand's current chart? Charts change between seasons. Trust the store you're buying from.