Ring Size Calculator

By CalculatorInn Team · Updated: 2026-03-22 · Free & accurate · Instant results

Find your ring size by entering the inside circumference of a ring that fits or your finger measurement in millimeters.

Interactive Ring Size Calculator

JavaScript is required for the interactive calculator. Enable JavaScript to use this tool.

How to Use This Calculator

Step-by-Step Instructions

  1. Enter your circumference (mm)
  2. Enter your us/canada size
  3. Enter your uk size
  4. Enter your eu size
  5. Enter your diameter
  6. Enter your circumference
  7. Results appear instantly — no button needed

Formula

Mathematical Formula

US Size ≈ (Circumference mm − 36.5) / 2.55

How It Works

US Size ≈ (Circumference mm − 36.5) / 2.55

Frequently Asked Questions

How does this work?

Enter your values in the fields above and the calculator will compute results instantly using the formula shown.

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