RingSizes

Ring Size Conversion — US ⇄ UK ⇄ EU ⇄ FR ⇄ DE ⇄ JP ⇄ CN

Who this is for: For anyone buying from an international jeweller, inheriting a foreign-marked ring, or selling rings across borders.

Convert any size between US, UK, EU, French, German, Japanese and Chinese systems — both directions.

Quick answer: One ring, one truth: inside circumference in mm. US 7 = UK N½ = EU 54 = FR 14.3 = IT 14 = DE 17.5 = JP 13. Convert from millimetres when a listing offers them; convert from US or UK sizes when it doesn't — this tool does both.

Pick the system your ring or listing uses.

Millimetres

US
6.75
UK
N
EU / ISO
54
Japan / China
12
Circumference54.0 mm · 5.4 cm · 2.13 in
Inside diameter17.19 mm
FrenchFR 13.7
Italian / Spanish / SwissIT 14
German (diameter)DE 17
Store charts round to whole sizes and drop half steps — convert from the millimetre figure whenever a listing provides one.
EU/ISO is the inside circumference in millimetres — the one number every system shares. FR and IT run 40 below ISO; DE is the inside diameter rounded.
Core facts
US 7 equalsUK N½ · EU 54 · JP 13
EU/ISO 8653Circumference in mm
FR & ITISO − 40
DEDiameter, rounded
UK scaleBS 6820 letters
JP = CNEast-Asia numbers

How do I convert ring sizes between countries?

Every system measures the same physical ring, so conversion is translation, not guesswork. US and Japanese sizes are numbered scales; UK is alphabetical (BS 6820); EU/ISO states the inside circumference in millimetres; French and Italian subtract 40 from that figure; German rounds the inside diameter. Choose the system your ring or listing uses, type the size, and the tool computes the rest from the ISO circumference — the one number all systems share.

Common uses

  • Convert a US 7 to UK, EU, French and Japanese before buying from an EU shop
  • Decode a vintage ring stamped with a UK letter or an Italian number
  • Translate your known size into Japanese sizing for a JP marketplace order
  • Check a seller's 'size 54' (ISO mm) against your US quarter size

Frequently Asked Questions

What is a US 7 in UK and EU sizes?
US 7 = UK N½ = EU 54 (ISO mm) = French 14.3 = Italian 14 = German 17.5 = Japanese 13. The EU figure is simply the inside circumference in millimetres.
Are UK and Australian ring sizes the same?
Yes — Australia and Ireland use the UK BS 6820 letter scale. A UK N½ is also an Australian N½ and an Irish N½.
Do Japanese and Chinese ring sizes match?
Yes, Japan and China share the East-Asia numbering (US 7 = JP 13). Japan's system steps about 1.25 mm of circumference per size, so it moves twice as fast as US quarter steps.
Why is my converted size off by half from a store's chart?
Store charts round to whole sizes and some drop half steps entirely. Convert from the millimetre figure whenever a listing provides one — it's the only number with no rounding drift.

More ring size charts

Ring Size Chart
Full US 3–16 chart with UK, EU, French, German and Japanese columns — filter, highlight and print.
Men's Ring Size Chart
US 8–15 chart for men, with the wide-band and knuckle adjustments that move men's sizes most.
Ring Size Chart in cm
The full chart in centimetres — 4.4 to 7.7 cm circumference with every US and UK equivalent.
Printable Ring Size Chart
A print-ready ring sizer with a credit-card calibration box — print, cut, wrap, read.

Related guides

  • How to Measure Ring SizeFour accurate home methods — existing ring, paper strip, calibrated printable, and the gift secret-weapon.
  • The Complete Ring Size GuideEvery sizing system explained, quarter sizes, width and knuckle rules, and what resizing costs.
  • 7 cm in Ring SizeExactly what 7 cm of circumference converts to — with the math many blogs get wrong.
  • Average Ring SizeWhat the average man and woman wear, how build shifts it, and how to guess well for gifts.
  • Ring Size 8Everything about US size 8: exact millimetres, international equivalents, and who wears it.