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Ring Size Converter

Convert ring sizes between US, EU, and Japanese systems, with diameter and circumference.

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What Is Ring Size Converter?

The Ring Size Converter turns a US ring size into its EU, Japanese, diameter, and circumference equivalents. Enter any half size from US 3 to 13 to see the millimeter measurements jewelers actually work with, so you can order confidently from any country.

Who Uses the Ring Size Converter?

Engagement ring buyers, online jewelry shoppers, and gift givers use it to match sizes across US, European, and Japanese sizing.

How to Use the Ring Size Converter

  1. Type the US ring size, halves allowed.
  2. Read the EU size, Japanese size, diameter, and circumference.
  3. Compare the millimeter figures with the jeweler chart.

Why Choose Our Ring Size Converter?

  • US, EU, and JP systems plus true millimeter measurements
  • Half-size precision with automatic snapping
  • Diameter and circumference for jeweler charts

Try the Ring Size Converter above — it is free, fast, and works on any device. Bookmark this page to return whenever you need it.