CM to Ring Size Converter Calculator
Convert centimeter measurements to international ring sizes with precision
Convert CM to Ring Size
Measure around the inside of the ring
Typical range: 3.5-7.0 cm for circumference, 1.1-2.2 cm for diameter
Calculated Measurements
How to Measure Your Ring Size
Cut a Strip of Paper
Cut a narrow strip of paper about 10cm long and 5mm wide.
Wrap Around Finger
Wrap the paper around the base of your finger where the ring will sit.
Mark the Overlap
Mark where the paper overlaps with a pen or pencil.
Measure with Ruler
Measure the length from the start to the mark in centimeters. This is your circumference.
Ring Sizing Tips
Measure when your hands are at normal temperature
Measure at the end of the day when fingers are largest
Make sure the ring can slide over your knuckle
Measure multiple times for accuracy
Consider wider bands need larger sizes
Ring Size Systems
US & Canada
Numerical system (0-13+) with half sizes
UK & Australia
Alphabetical system (A-Z) with quarter sizes
France & Russia
Circumference in millimeters
Germany
Diameter in millimeters
Japan
Numerical system (1-27)
Switzerland
Circumference-based numerical system
Understanding Ring Size Conversion
Why Accurate Measurement Matters
Getting the right ring size is crucial for comfort and wearability. A ring that's too tight can restrict blood flow and be uncomfortable, while a ring that's too loose might slip off and get lost.
Common Measurement Mistakes
- •Measuring when hands are cold or swollen
- •Not considering knuckle size
- •Using non-flexible measuring tools
- •Measuring different fingers inconsistently
Professional vs. Home Measurement
While this calculator provides accurate conversions, professional jewelers use specialized tools like ring mandrels and sizing rings for the most precise measurements.
When to Seek Professional Help
- •Expensive jewelry purchases
- •Custom or unique ring designs
- •Wide band rings (6mm+)
- •Medical conditions affecting finger size