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Ring Size Converter

Perform accurate calculations for Ring Size Converter.

Convert ring sizes across US, UK (letter), EU (circumference mm), India (UK letters), and Japan (diameter mm). Enter any supported input and click Convert.

This converter uses a standard international ring size chart as its base. It first converts your input into a standardized metric (inner circumference in mm). Then, using that standard measurement, it finds the closest matching sizes in all other regional systems, including interpolating for US sizes for greater accuracy.

The Ultimate Guide to Ring Sizes: Find Your Perfect Fit in US, UK, EU, India & Japan

Finding the perfect ring size can be surprisingly tricky — what fits perfectly in one country might feel loose or tight in another. That’s why having a ring size converter is essential when buying or gifting jewelry internationally.

In this guide, we’ll walk you through everything you need to know about ring size measurement, conversion between US, UK, EU, India, and Japan, and how to measure your ring size at home — with clear charts, formulas, and tips.

Why Ring Size Matters

A ring that’s too tight can be uncomfortable or get stuck, while a loose one can fall off and get lost. Knowing your exact ring size saves you from resizing fees, returns, and the disappointment of an ill-fitting piece.

How Ring Sizes Are Measured

Ring sizes are based on the inner circumference or diameter of the ring. Each country uses its own system:

  • US Sizes: Numeric (e.g., 7, 8, 9) based on a scale derived from inches.
  • UK/India Sizes: Alphabetic (e.g., M, N, O) based on circumference.
  • EU Sizes: Numeric (e.g., 52, 54) based directly on the inner circumference in millimeters.
  • Japan Sizes: Numeric (e.g., 14, 15) based on inner diameter in millimeters.

How to Measure Ring Size at Home

Method 1: Using a String or Paper Strip
Wrap a string or strip of paper around the base of your finger. Mark where it overlaps. Measure the length in millimeters — this is your circumference, which corresponds to your EU size.

Method 2: Using an Existing Ring
Take a ring that fits perfectly. Measure the inner diameter in millimeters. Use the chart below to find your equivalent size.

Ring Size Conversion Chart

USUK/IndiaDiameter (mm)Circumference (mm)EUJapan
5J15.749.3509
6L16.551.85212
7N17.354.45414
8P18.157.05616
9R18.959.55918
10T19.862.16320
11V20.664.66623
12X21.467.26827

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Ring Size Converter

Perform accurate calculations for Ring Size Converter.

How to use Ring Size Converter

Step-by-step guide to using the Ring Size Converter:

  1. Enter your values. Input the required values in the calculator form
  2. Calculate. The calculator will automatically compute and display your results
  3. Review results. Review the calculated results and any additional information provided

Frequently asked questions

How do I use the Ring Size Converter?

Simply enter your values in the input fields and the calculator will automatically compute the results. The Ring Size Converter is designed to be user-friendly and provide instant calculations.

Is the Ring Size Converter free to use?

Yes, the Ring Size Converter is completely free to use. No registration or payment is required.

Can I use this calculator on mobile devices?

Yes, the Ring Size Converter is fully responsive and works perfectly on mobile phones, tablets, and desktop computers.

Are the results from Ring Size Converter accurate?

Yes, our calculators use standard formulas and are regularly tested for accuracy. However, results should be used for informational purposes and not as a substitute for professional advice.