Ring Size Calculator
Convert ring sizes by finger circumference or diameter across US, UK, EU, JP, CN and 10+ international standards
Calculator Interface
Interactive calculator will be available soon
Features
- ✓ Convert by finger circumference (mm) or diameter (mm)
- ✓ Supports US, UK, EU, JP, CN and 10+ ring size standards
- ✓ Built-in circumference-diameter-size lookup table with <0.5mm accuracy
- ✓ International size comparison with online shopping recommendations
- ✓ 100% local calculation — no data leaves your browser
How to Use
- Wrap a soft tape or paper strip around your finger and measure the circumference (mm)
- Choose measurement type (circumference or diameter) and enter the value
- Select the target size standard (US/UK/EU/JP/CN etc.)
- Click convert to see your ring size and sizing tips
FAQ
What is Ring Size Calculator?
An online ring size conversion tool. It converts ring sizes by finger circumference or diameter across US, UK, EU, JP, CN and 10+ international standards. Input: your finger circumference or diameter. Output: your ring size in multiple standards with one-click copy. Everything runs in your browser — no uploads.
How do I measure my finger circumference?
Wrap a soft tape or a strip of paper around the base of your finger, mark where it overlaps, then measure the length — that is your circumference (mm). Measure in the evening or when your hands are warm for the most accurate everyday size.
What is the difference between country ring size standards?
Different countries use different systems: US and Canada use numbers, UK uses letters, EU uses larger numbers, while JP and CN use the inner circumference in millimeters. This tool includes a complete conversion table.
Are the results accurate?
As long as your circumference is measured accurately (within 0.5mm), the conversion is precise. Measure a few times and take the average, adjusting for band width and wearing habits.
Should I size up or down when buying rings online?
Generally: measure in summer or after exercise for an exact fit, or size up half a size in winter; wide bands (6mm+) run about half a size larger than slim bands; if your knuckles are wider, choose a size that passes over the knuckle comfortably.
Can I save the conversion result?
Yes. Results can be copied with one click, and the multi-country comparison table can be saved as an image for reference when shopping offline.