Finding the perfect ring size can be tricky, especially when shopping internationally or ordering a surprise engagement ring. Whether you’re in the United Kingdom, Europe, or beyond, ring sizing varies by measurement systems—from alphabetical systems to numerical scales, and mm/inches to internal diameters. That’s why we at Lords have created this comprehensive ring size guide to help you navigate international conversions and explain measurement standards clearly and concisely.
Why Ring Size Matters
The right fit is essential—not too loose that it slips off, nor too tight that it causes discomfort. Rings should fit comfortably yet securely. Factors such as cold temperatures, weight loss, and wider bands can affect how a ring feels on your finger. Knowing your accurate size is the first step toward the perfect fit.
How to Measure Your Ring Size at Home
There are several simple ways to measure your ring size without leaving home. Before jumping into charts and conversions, here are a few DIY methods:
1. Use an Existing Ring
If you already own a ring that fits the intended finger, place it on a ruler and measure the internal diameter in millimetres. Match this number to a ring size chart (we’ll provide one below) for your region or convert it to other countries’ sizes.
2. Use a Ring Sizer
A ring sizer tool is the most accurate way to measure your finger at home. These are usually adjustable and provide direct readings in various sizing systems such as UK sizes, ISO sizes, or metric measurements.
3. The String or Paper Strip Method
- Cut a piece of string or a thin paper strip.
- Wrap it around the base of the finger where the ring will sit.
- Mark where the ends meet.
- Measure the length in mm—this gives you the inner circumference.
- Match this with a conversion chart to find your size.
Tip: Measure your finger at the end of the day, when it’s at its largest. Avoid measuring in cold temperatures, as fingers shrink slightly.
Understanding International Ring Size Systems
Different countries use different systems, making ring size conversion essential for global shoppers. Below are the most commonly used measurement systems:
1. United Kingdom
- Uses an alphabetical system from A to Z+.
- Includes half sizes (e.g., M½, N½).
- Common for jewellery in the UK and former Commonwealth countries.
2. United States and Canada
- Based on a numerical scale, typically from size 3 to 13.
- Includes quarter sizes (e.g., 5¼, 6½).
3. European System (ISO)
- Based on the inner circumference of the ring in millimetres.
- Used in many European countries and often referred to as the ISO size.
4. German System
- Similar to the ISO system, but usually rounded.
- May differ slightly in half sizes.
5. Japanese and Chinese Sizes
- Use a simple numerical scale, but values are entirely different from the US or UK systems.
Ring Size Conversion Chart
Here’s a handy ring size conversion chart that covers the UK, US/Canada, European, and Japanese systems.
| UK Size | US Size | European Size (mm) | Inside Diameter (mm) | Circumference (mm) |
| J | 4 3/4 | 48 | 15.49 | 48.7 |
| K | 5 1/4 | 50 | 15.9 | 50.0 |
| L | 5 3/4 | 51.5 | 16.31 | 51.2 |
| M | 6 1/4 | 52.5 | 16.71 | 52.5 |
| N | 6 3/4 | 54 | 17.12 | 53.8 |
| O | 7 1/4 | 55 | 17.53 | 55.0 |
| P | 7 3/4 | 56.5 | 17.93 | 56.3 |
| Q | 8 1/4 | 57.5 | 18.34 | 57.6 |
| R | 8 3/4 | 59 | 18.75 | 58.9 |
| S | 9 1/4 | 60.5 | 19.15 | 60.2 |
| T | 9 3/4 | 61.5 | 19.56 | 61.5 |
| U | 10 1/4 | 62.5 | 19.96 | 62.7 |
| V | 10 3/4 | 64 | 20.37 | 64.0 |
| W | 11 1/4 | 65 | 20.78 | 65.3 |
| X | 11 3/4 | 66.5 | 21.18 | 66.6 |
| Y | 12 1/4 | 67.5 | 21.59 | 67.9 |
| Z | 12 3/4 | 69 | 22.0 | 69.1 |
| Z+1 | 13 1/4 | 70.5 | 22.4 | 70.4 |
This conversion chart makes it easier to find your perfect ring size across regions.
Ring Sizing Tips and Considerations
- Fingers swell and shrink during the day and with weather changes.
- A ring should feel tighter in the morning and looser in the evening.
- Wider bands may require a larger size than thinner ones.
- Measure multiple times and average the results for the most accurate.
Common Ring Sizes for Women and Men
While ring sizes vary greatly, there are some averages:
- Women’s average size: UK M–O / US 6–7.5
- Men’s average size: UK T–V / US 9–10.5
If you’re buying a ring as a gift and don’t know the size, it’s best to use an existing ring or discreetly ask for their finger size, or simply borrow a ring they wear on the correct finger and use that for sizing.
What If You’re Between Sizes?
If your measurement falls between two sizes (e.g., 6½ and 7), consider:
- Going up a half size if the ring has a wider band.
- Going down if the ring is thin or the finger is on the smaller side. Consult a professional jeweller to find the best fit.
Need Help? Contact Lords
At Lords, we understand that selecting the right ring involves more than just design—ring size plays a huge role in comfort and wearability. If you’re still unsure or would like professional help, feel free to reach out to our expert team. Contact us or visit us in-store.
We’re here to make sure your ring fits like a dream.
Conclusion
Choosing the right size shouldn’t be guesswork. With this ring size guide, we hope you now understand how to measure your ring size, interpret different measurement systems, and convert sizes across the globe. Use our ring size conversion chart, whether you’re shopping locally or ordering from other countries, to ensure the perfect fit every time.Ready to find your ideal ring? Explore our collection at Lords and let us help you find the one that fits just right.