Ring Size Guide
US & Canada Ring Sizes
| US Size | Diameter (mm) | Circumference (mm) |
|---|---|---|
| 3 | 14.1 | 44.2 |
| 3.5 | 14.5 | 45.5 |
| 4 | 14.9 | 46.8 |
| 4.5 | 15.3 | 48.0 |
| 5 | 15.7 | 49.3 |
| 5.5 | 16.1 | 50.6 |
| 6 | 16.5 | 51.9 |
| 6.5 | 16.9 | 53.1 |
| 7 | 17.3 | 54.4 |
| 7.5 | 17.7 | 55.7 |
| 8 | 18.2 | 57.0 |
| 8.5 | 18.6 | 58.3 |
| 9 | 19.0 | 59.5 |
| 9.5 | 19.4 | 60.8 |
| 10 | 19.8 | 62.1 |
| 10.5 | 20.2 | 63.4 |
| 11 | 20.6 | 64.6 |
| 11.5 | 21.0 | 65.9 |
| 12 | 21.4 | 67.2 |
UK & Australia Ring Sizes
| UK Size | Diameter (mm) | Circumference (mm) |
|---|---|---|
| F | 14.1 | 44.2 |
| G | 14.5 | 45.5 |
| H | 14.9 | 46.8 |
| I | 15.3 | 48.0 |
| J | 15.7 | 49.3 |
| K | 16.1 | 50.6 |
| L | 16.5 | 51.9 |
| M | 16.9 | 53.1 |
| N | 17.3 | 54.4 |
| O | 17.7 | 55.7 |
| P | 18.2 | 57.0 |
| Q | 18.6 | 58.3 |
| R | 19.0 | 59.5 |
| S | 19.4 | 60.8 |
| T | 19.8 | 62.1 |
| U | 20.2 | 63.4 |
| V | 20.6 | 64.6 |
| W | 21.0 | 65.9 |
| X | 21.4 | 67.2 |
European Ring Sizes
| EU Size | Diameter (mm) | Circumference (mm) |
|---|---|---|
| 44 | 14.1 | 44.2 |
| 45 | 14.5 | 45.5 |
| 46 | 14.9 | 46.8 |
| 48 | 15.3 | 48.0 |
| 49 | 15.7 | 49.3 |
| 50 | 16.1 | 50.6 |
| 52 | 16.5 | 51.9 |
| 53 | 16.9 | 53.1 |
| 54 | 17.3 | 54.4 |
| 56 | 17.7 | 55.7 |
| 57 | 18.2 | 57.0 |
| 58 | 18.6 | 58.3 |
| 60 | 19.0 | 59.5 |
| 61 | 19.4 | 60.8 |
| 62 | 19.8 | 62.1 |
| 63 | 20.2 | 63.4 |
| 65 | 20.6 | 64.6 |
| 66 | 21.0 | 65.9 |
| 67 | 21.4 | 67.2 |
Japanese Ring Sizes
| JP Size | Diameter (mm) | Circumference (mm) |
|---|---|---|
| 4 | 14.5 | 45.5 |
| 5 | 14.9 | 46.8 |
| 6 | 15.3 | 48.0 |
| 7 | 15.7 | 49.3 |
| 8 | 16.1 | 50.6 |
| 9 | 16.5 | 51.9 |
| 10 | 16.9 | 53.1 |
| 11 | 17.3 | 54.4 |
| 12 | 17.7 | 55.7 |
| 13 | 18.2 | 57.0 |
| 14 | 18.6 | 58.3 |
| 15 | 19.0 | 59.5 |
| 16 | 19.4 | 60.8 |
| 17 | 19.8 | 62.1 |
| 18 | 20.2 | 63.4 |
| 19 | 20.6 | 64.6 |
| 20 | 21.0 | 65.9 |
| 21 | 21.4 | 67.2 |
Find Your Ring Size
Measure Your Finger
- Use a flexible measuring tape or length of string.
- Wrap it around the finger you'll wear your ring on. If you're creating a ring stack, consider where on your finger the ring will sit. If using string, mark the point on the string where the ends meet with a pen.
- Lay the string on a flat surface and use a ruler to measure the length (in inches or millimeters) up to the mark. Compare your measurement to the size chart to determine your ring size. If you are between sizes, opt for the larger size.
Measure an Existing Ring
- Choose a ring that already fits your finger well.
- Measure the interior diameter of the ring in millimeters (mm).
- Use the measurement chart to match the size of your ring to the closest size in mm. The interior of the ring should align with the outer edge of the circle.
Luther's At Your Service
There's no question too small or request too large for Luther's Diamonds client advisors. From choosing an engagement ring or gift to providing in-store or virtual appointments, we're always at your service.
Watch how your ring is made.
Every ring that leaves our studio passes through these stages — cast, ground, set, and hand-polished. Not by a factory line. By the same small team, in the same small workshop, for over a decade.
Grinding After Casting
Once the gold is cast in its rough form, every surface is carefully ground down by hand to reveal the ring's true silhouette.
Setting the Stones
Each stone is placed by hand and secured into its setting — one at a time, under magnification, with full attention to symmetry and seat.
Hand Polished
We still hand-polish every ring. No tumblers, no shortcuts. The mirror finish you see is the result of progressively finer abrasives, worked by hand until the metal sings.
Finished Ring
Before it ships, every ring is inspected one last time by Jack — checking the stone seat, the polish, the comfort of the band — and only then does it leave the workshop.
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Stories from the people who said yes.
Every ring we make passes through our family workshop before it reaches a doorstep. Below are the moments that followed — in their own words, with their own photos.
I bought this ring to celebrate a new chapter in my life, and honestly… best decision I've made in a while. The craftsmanship is stunning. The diamond has serious presence without being loud (hidden halo), and the setting is elegant, timeless, and very 'put-together.' I've gotten so many compliments. Thank you Jack, thank you for the amazing family team to make this happen.
Creating the perfect engagement ring was super easy with Luther's Diamonds. From start to finish, they ensured every detail was exactly what I envisioned. The 1:1 CAD model was such a reassuring step in the process, giving me the confidence that this ring was going to be everything I dreamed of and more. I'm so grateful for their expertise, and my fiancée couldn't be happier with the final result!
The proposal was perfect, and the ring truly exceeded everything I imagined. Jack & the team created something incredibly special, and seeing my fiancée’s reaction made me realize even more how much care and craftsmanship went into it. It never felt like just buying a ring — it genuinely felt personal from beginning to end, and that’s something we’ll always remember.
The ring looks amazing!!! I had it shipped to my uncle's place to keep it a secret, and the team communicated everything perfectly. They really understood my situation and helped make sure this ring stayed part of the secret project. PURE perfection!
The details on this ring… I cannot put into words!!! More I look at it, more stunning it is :)
Definitely coming back for a wedding band, as this ring is stackable!!!
The close-up details on this ring are unreal. Thank you, Jack, for working with my fiancé (husband now) and arranging delivery as well.
She loved it. Highly recommended :)
Gosh I love this ring!
Why our clients actuallytrust us.
We're a family workshop, not a marketplace. Every ring is made by hand, every stone reviewed by Jack himself before it's set, and every order followed personally — start to finish.
Made by One Family
Hand-crafted in our workshop by the same small team — Jack and family — who answer every email and approve every ring before it ships.
Lifetime Warranty
Covered for manufacturing defects, for life. If a gemstone ever loosens, we'll send you a replacement stone.
Honest Timing
Made-to-order takes 3-5 weeks. We tell you up front, we update you along the way, and we ship insured the moment your ring is ready.
Every ring that leaves our workshop carries our family name. That's why we treat each one like it's going to someone in ours.