Ring Size Guide | Diamond Lab Australia
Ring Size Guide – Find Your Perfect Fit with Diamond Lab
At Diamond Lab, we believe the perfect ring deserves the perfect fit. Whether you're designing a custom engagement ring in Brisbane, shopping for a wedding band in Perth, or browsing from Auckland, this comprehensive guide will help you find your ideal size with ease.
We use the Australian ring size system, which is identical to the UK and New Zealand sizing standards. We've also included conversions to US sizes, as well as precise inside diameter and circumference in millimetres, so you can confidently find the best fit from anywhere.
Complete Ring Size Conversion Chart
| AU / UK / NZ Size | US Size | Inside Diameter (mm) | Inside Circumference (mm) |
|---|---|---|---|
| F | 3 | 14.00 | 44.14 |
| F 1/2 | 3.25 | 14.20 | 44.60 |
| G | 3.5 | 14.40 | 45.26 |
| G 1/2 | 3.75 | 14.60 | 45.92 |
| H | 4 | 14.80 | 46.57 |
| H 1/2 | 4.25 | 15.00 | 47.12 |
| I | 4.5 | 15.20 | 47.78 |
| I 1/2 | 4.75 | 15.40 | 48.44 |
| J | 5 | 15.60 | 49.10 |
| J 1/2 | 5.25 | 15.80 | 49.75 |
| K | 5.5 | 16.00 | 50.41 |
| K 1/2 | 5.75 | 16.20 | 51.06 |
| L | 6 | 16.40 | 51.72 |
| L 1/2 | 6.25 | 16.60 | 52.37 |
| M | 6.5 | 16.80 | 53.03 |
| M 1/2 | 6.75 | 17.00 | 53.69 |
| N | 7 | 17.20 | 54.34 |
| N 1/2 | 7.25 | 17.40 | 55.00 |
| O | 7.5 | 17.60 | 55.66 |
| O 1/2 | 7.75 | 17.80 | 56.31 |
| P | 8 | 18.00 | 56.97 |
| P 1/2 | 8.25 | 18.20 | 57.62 |
| Q | 8.5 | 18.40 | 58.28 |
| Q 1/2 | 8.75 | 18.60 | 58.94 |
| R | 9 | 18.80 | 59.59 |
| R 1/2 | 9.25 | 19.00 | 60.25 |
| S | 9.5 | 19.20 | 60.90 |
| S 1/2 | 9.75 | 19.40 | 61.56 |
| T | 10 | 19.60 | 62.22 |
| T 1/2 | 10.25 | 19.80 | 62.87 |
| U | 10.5 | 20.00 | 63.53 |
| U 1/2 | 10.75 | 20.20 | 64.18 |
| V | 11 | 20.40 | 64.84 |
| V 1/2 | 11.25 | 20.60 | 65.50 |
| W | 11.5 | 20.80 | 66.15 |
| W 1/2 | 11.75 | 21.00 | 66.81 |
| X | 12 | 21.20 | 67.46 |
| X 1/2 | 12.25 | 21.40 | 68.12 |
| Y | 12.5 | 21.60 | 68.77 |
| Y 1/2 | 12.75 | 21.80 | 69.43 |
| Z | 13 | 22.00 | 70.09 |
| Z+ | 13.25+ | 22.30–23.00+ | 70.90–72.30+ |
How to Measure Your Ring Size
- Visit our Perth showroom for a professional fitting.
- Book a virtual appointment to measure with our help.
- Measure the inside diameter of a ring you already wear.
- Request a printable sizing guide from our team.
Please note: We do not offer complimentary ring sizers, but we’re happy to assist you personally. Contact us here or book an appointment for help.
Why Ring Size Accuracy Matters
All Diamond Lab rings are crafted to order. Choosing the correct size ensures not only comfort, but also the long-term security and wearability of your ring. A snug but not tight fit is ideal, especially for engagement and wedding rings worn every day.
If you're purchasing a surprise ring, consider measuring a ring your partner already wears on the correct finger or choosing a common size (such as M or N) and resizing after delivery if needed.
Ring Size FAQs
Can I resize my ring after purchase?
Yes, most Diamond Lab rings can be resized. We will let you know if your chosen design has any limitations.
Are Australian and New Zealand ring sizes the same?
Yes, they both use the same alphabetical ring sizing system, also known as the UK format.
Do you offer sizes beyond what’s shown?
Yes, we can accommodate smaller or larger sizes including Z+ and custom fits. Just let us know your measurement.
Do wider bands fit tighter?
Yes, wider bands tend to feel firmer. If your ring is 4mm or wider, we may suggest sizing up slightly.
What if I’m between two sizes?
We recommend going with the larger size for comfort, especially in warmer climates. Our team is happy to advise.
