Ring Size Converter
Convert ring sizes between international standards and measurements
Ring Size Converter
Measure the inside diameter of the ring
How to Measure Ring Size
Example Conversion
Common Ring Size Example
Finger circumference: 55mm (measured with string)
Calculated diameter: 55mm ÷ 3.14159 = 17.51mm
Closest standard size:
- • US & Canada: Size 7.5
- • UK & Australia: Size P
- • EU & France: Size 56.5
- • Germany: Size 17.75
Ring Size Standards
US & Canada
Numerical system (3, 3.5, 4, etc.)
UK & Australia
Alphabetical system (A, B, C, etc.)
European
Circumference in mm (50, 52, 54, etc.)
Ring Sizing Tips
Measure at the end of the day when fingers are largest
Consider the width of the ring - wider rings need larger sizes
Don't measure when your hands are cold or hot
Each finger may be a different size - measure the correct finger
Ring should slide over knuckle but fit snugly at base
Understanding Ring Sizes and International Standards
Why Ring Size Conversion Matters
Different countries use different ring sizing systems, making it essential to convert between standards when buying rings internationally or online. Our converter ensures you get the perfect fit regardless of the sizing system used.
How Ring Sizes Are Measured
- •Inner Diameter: The distance across the inside of the ring
- •Inner Circumference: The distance around the inside of the ring
- •Relationship: Circumference = π × Diameter
International Sizing Systems
US & Canada
Uses numerical sizes starting from 0, incrementing by 0.25 or 0.5
UK & Australia
Uses alphabetical system from A to Z, with half sizes
European
Based on inner circumference in millimeters
Professional Ring Sizing Methods
Jewelry Store
Most accurate method using professional ring sizers and mandrels
String Method
Wrap string around finger and measure length for circumference
Existing Ring
Measure the inner diameter of a well-fitting ring