Ring Size Letter to Number
Ring Size Letter to Number Converter
Convert UK ring size letters (A-Z) to US ring size numbers (1-13). Simple, accurate conversion between letter-based and number-based ring sizing systems.
Size Converter
Single letter A-Z
Converted Sizes
Reference Table
| US | UK | EU | JP | AU | CH | DE | mm | mm (Circ) |
|---|---|---|---|---|---|---|---|---|
| 3 | F | 44 | 4 | F | 4 | 14 | 14.1 | 44.2 |
| 3.5 | G | 45 | 5 | G | 5.25 | 14.5 | 14.5 | 45.5 |
| 4 | H | 46.5 | 7 | H | 6.5 | 15 | 14.9 | 46.8 |
| 4.5 | I | 48 | 8 | I | 7.75 | 15.25 | 15.3 | 48 |
| 5 | J 1/2 | 49 | 9 | J 1/2 | 9 | 15.75 | 15.7 | 49.3 |
| 5.5 | L | 50.5 | 10 | L | 10.25 | 16 | 16.1 | 50.6 |
| 6 | M | 52 | 12 | M | 11.5 | 16.5 | 16.5 | 51.9 |
| 6.5 | N | 53 | 13 | N | 12.75 | 17 | 16.9 | 53.1 |
| 7 | O | 54.5 | 14 | O | 14 | 17.25 | 17.3 | 54.4 |
| 7.5 | P | 56 | 15 | P | 15.25 | 17.75 | 17.7 | 55.7 |
| 8 | Q | 57 | 16 | Q | 16.5 | 18 | 18.1 | 57 |
| 8.5 | R | 58.5 | 17 | R | 17.75 | 18.5 | 18.5 | 58.3 |
| 9 | S | 59.5 | 18 | S | 19 | 19 | 19 | 59.5 |
| 9.5 | T | 61 | 19 | T | 20.25 | 19.5 | 19.4 | 60.8 |
| 10 | U | 62 | 20 | U | 21.5 | 20 | 19.8 | 62.1 |
| 10.5 | V | 63.5 | 22 | V | 22.75 | 20.25 | 20.2 | 63.4 |
| 11 | W | 65 | 23 | W | 24 | 20.75 | 20.6 | 64.6 |
| 11.5 | X | 66 | 24 | X | 25.25 | 21 | 21 | 65.9 |
| 12 | Y | 67.5 | 25 | Y | 26.5 | 21.25 | 21.4 | 67.2 |
| 12.5 | Z | 69 | 26 | Z | 27.75 | 21.75 | 21.8 | 68.5 |
| 13 | Z+1 | 70 | 27 | Z+1 | 29 | 22.25 | 22.2 | 69.7 |
Frequently Asked Questions
📏 How to Measure Your Ring Size
Method 1: String or Paper
The most common way to measure at home. Follow these steps carefully:
- Wrap a strip of paper or string around the base of your finger.
- Mark the point where the ends meet with a pen.
- Measure the string or paper with a ruler (mm).
Method 2: Existing Ring
If you have a ring that fits well, use this method:
- Place your ring on a flat surface.
- Place a ruler on top of the ring.
- Measure the inner diameter (inside edge to inside edge).
💡 Pro Tip: Avoid Common Mistakes
Don't pull the string too tight!
The paper or string should fit snugly around your finger, but not so tight that it squeezes your skin. It needs to be able to slide over your knuckle with just a little bit of resistance.
✓ Correct: Snug fit, comfortable
✗ Incorrect: Squeezing finger, too tight
🛡️ Our Methodology & Accuracy Standards
Data Verification: All ring size conversion data is cross-referenced against the ISO 8653:2016 jewelry sizing standard and official manufacturer charts from major international jewelry retailers.
Precision Calculation: Conversions between diameter and circumference use a high-precision constant for π (3.1415926535), ensuring that millimeter results are accurate to within 0.01mm.
Regional Authority: We distinguish between true EU sizing (circumference in mm) and the older DE/Central European standards. Our UK scaling adheres to the traditional British Standard 1283.
Continuous Updates: Our database is reviewed regularly for changes in international manufacturing tolerances to provide reliable, up-to-date guidance for jewelry shopping.
Related Ring Size Tools
Explore related conversion tools to find exactly what you need
Ring Size Converter
Full conversion tool for all regions
Inches to Ring Size
Convert inches to ring sizes
CM to Ring Size
Convert centimeters to ring sizes
European to US Ring Size
Convert EU to US ring sizes
Ring Size Conversion Chart
Complete ring size reference table
International Ring Size Chart
Global ring size comparison
💡Quick Answer
UK ring sizes use letters (A-Z), while US sizes use numbers (1-13). UK size N equals US size 7. Use our converter for instant letter-to-number conversions.