Ring Size Converter: US, UK, EU and Japan, Plus a Printable Sizer
Convert a ring size between US, UK, EU and Japan, or turn a finger measurement into a size. Includes a printable sizer with a card-width scale check. Chart values are unverified. Runs in your browser.
Your numbers stay in this browser. Nothing is uploaded or sent to a server. Chart values are UNSOURCED and brands differ, so check the seller's own chart.
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Nothing is sent until you press Send. Your measurements are included only if you tick the box, and you can see the full report below first.
When to use this
- You know your ring size in one country and the shop lists sizes in another.
- You measured your finger or a ring you own and want the matching size.
- You want a printable sizer and a way to check that your printer did not shrink it.
How to use
- Choose what you know: a size, the circumference of your finger, or the diameter of a ring you own.
- Type the value and press Convert ring size.
- Read the US, UK, EU and Japan sizes. If you are between sizes, the tool shows both neighbours.
- To use the printable sizer, print the page at 100 percent, measure the printed card outline and type its width. The tool tells you if the print scale needs changing.
Examples
- US 7 in other countries: US 7 is an inside circumference of 54.4 mm and a diameter of 17.3 mm. In the built-in chart that is UK N 1/2, EU 54 and Japan 14.
- A finger measured at 2.2 inches: 2.2 in is 55.88 mm. The nearest chart size is US 7.5 (55.7 mm), a difference of 0.18 mm.
- A printed card that is too small: If the printed card outline measures 80 mm instead of 85.6 mm, print again at 107 percent.
Understanding the result
A size converts through the inside circumference in millimetres. A diameter is multiplied by pi to get the circumference. A measurement is matched to the nearest chart row and counts as a match when it is within 0.3 mm. Past that the tool shows the two sizes around it. Every chart value is UNSOURCED: it is a commonly published figure that was not checked against a brand or a standard.
Limitations
- Chart values are UNSOURCED. They are not taken from a standards document or a brand. Brands and jewelers differ, so check the seller's own chart.
- Wide bands fit tighter than thin ones, and knuckle size, temperature and time of day change what fits. The tool does not adjust for any of this.
- The printable sizer is only as accurate as your printer. Use the card outline to check it, and if the card does not fit exactly, do not use the sizer.
- This is not medical or jewelry-making advice. For a ring that is a gift or an expensive piece, have it measured by a jeweler.
FAQ
How do I convert a US ring size to UK?
Pick US / Canada, type your size such as 7 and press Convert. The tool shows the UK letter on the same chart row, for example N 1/2. Different charts can differ by half a size.
How do I measure my ring size at home?
Wrap a thin strip of paper or string around the base of the finger, mark where it overlaps, measure the length with a ruler and type it as a circumference. Measure at the end of the day, when the finger is warm, and repeat it a few times.
What if I am between two sizes?
The tool shows both neighbours. A wide band usually needs the larger one and a thin band the smaller one, but ask the seller, because brands differ.
Is the printable ring sizer accurate?
Only if it prints at the right scale. Lay a bank card on the card outline: it must fit exactly. If it does not, measure the outline, type the width in the scale check and print again at the scale the tool gives.
Are my numbers sent anywhere?
No. The conversion runs in your browser. Nothing you type is uploaded or sent to a server.
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