Why is JP cm the canonical unit?

Japanese sizing is the Mondopoint system (foot length in cm), which is also the basis of ISO/TS 19407. Even US/UK Brannock devices ultimately measure in mm, so we normalise to JP cm first and derive the other regions from there.

Why are US and UK sizes different?

Both use the historical barleycorn (≈ 8.46 mm) step, but they start at different points. Roughly, US men ≈ UK + 1, so the same foot reads about one size larger in US. For women the offset is bigger (US ≈ UK + 2).

How is the EU size calculated?

The EU (Paris point) scale uses ≈ 6.67 mm per size and a typical formula (foot length cm + 1.5) × 3 / 2. We use a discrete chart aligned with major brand charts (Nike / Adidas / New Balance) and linearly interpolate by foot length.

How do Kids' US sizes work?

US kids' sizing goes through Toddler (T), Little Kid (US K 4–13) and Big Kid (US Y 1–7), and Big Kid 7 lines up with Men's 7 (≈ 25 cm). This tool uses a continuous numbering (US 5.5–15.5) without K/Y labels — JP cm ≥ 20.0 corresponds to the Big Kid range.

Why do brands feel different at the same labelled size?

Each brand uses its own last (width, instep height, toe spring), so an US 8 from one brand differs from another. Nike tends to run ~0.5 small, New Balance and ASICS are about standard, Vans and Converse run large. Always check the brand's own chart in cm for a critical purchase.

Is my input uploaded?

No. All computation runs in your browser and the values never leave the page.

Back to Convert

Shoe Size Converter (JP cm ⇄ US ⇄ UK ⇄ EU)

Convert shoe sizes between Japan (cm, Mondopoint), US, UK and EU. Handy when buying Nike, Adidas, New Balance, Vans, Dr. Martens or Birkenstock from overseas shops, or sanity-checking a gift bought abroad. Choose Men / Women / Kids with the radio buttons — the conversion table follows the Brannock device and major brand charts, but individual brands vary by ~0.5 sizes, so always double-check with the maker's own chart for a critical fit. Runs entirely in your browser — no uploads.

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How to use

1) Pick the audience radio (Men / Women / Kids) — each uses a different chart. 2) Pick the input unit (JP cm / US / UK / EU) and type a size value. 3) The other three units appear in the table instantly. Use the Copy button on any row to grab a single value. There is no run button; everything is live.

FAQ

Why is JP cm the canonical unit?: Japanese sizing is the Mondopoint system (foot length in cm), which is also the basis of ISO/TS 19407. Even US/UK Brannock devices ultimately measure in mm, so we normalise to JP cm first and derive the other regions from there.
Why are US and UK sizes different?: Both use the historical barleycorn (≈ 8.46 mm) step, but they start at different points. Roughly, US men ≈ UK + 1, so the same foot reads about one size larger in US. For women the offset is bigger (US ≈ UK + 2).
How is the EU size calculated?: The EU (Paris point) scale uses ≈ 6.67 mm per size and a typical formula (foot length cm + 1.5) × 3 / 2. We use a discrete chart aligned with major brand charts (Nike / Adidas / New Balance) and linearly interpolate by foot length.
How do Kids' US sizes work?: US kids' sizing goes through Toddler (T), Little Kid (US K 4–13) and Big Kid (US Y 1–7), and Big Kid 7 lines up with Men's 7 (≈ 25 cm). This tool uses a continuous numbering (US 5.5–15.5) without K/Y labels — JP cm ≥ 20.0 corresponds to the Big Kid range.
Why do brands feel different at the same labelled size?: Each brand uses its own last (width, instep height, toe spring), so an US 8 from one brand differs from another. Nike tends to run ~0.5 small, New Balance and ASICS are about standard, Vans and Converse run large. Always check the brand's own chart in cm for a critical purchase.
Is my input uploaded?: No. All computation runs in your browser and the values never leave the page.

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