Ring Size Chart in CM: Accurate Sizing for Custom-Fit Rings
When it comes to rings, precision matters. Whether you're investing in a custom engagement ring, a bespoke wedding band, or a one-of-a-kind statement piece, getting the size right is just as important as the design itself. That's why having a reliable ring size chart in cm is essential—especially if you're measuring at home or ordering internationally.
At Vermont Gem Lab, we’re committed to ensuring every piece of custom jewelry fits comfortably and perfectly. In this guide, we provide a detailed ring size chart in centimeters, explain how to measure your finger accurately at home, and share professional tips for finding your ideal fit.
Let’s help you size with confidence.
Why Accurate Ring Sizing Matters
A poorly fitting ring can cause discomfort, damage to the ring, or even risk being lost. Getting the correct size from the beginning ensures your ring will not only look beautiful but also feel secure and comfortable.
At Vermont Gem Lab, we custom-craft each ring for an exact fit based on your measurements—including half and quarter sizes.
Ring Size Chart in CM (Circumference-Based)
Below is a ring size conversion chart using centimeters (cm) and millimeters (mm) to help you match your measurement with U.S. standard ring sizes.
| US Size | Inside Circumference (cm) | Inside Circumference (mm) |
|---|---|---|
| 3 | 4.41 cm | 44.1 mm |
| 3.5 | 4.53 cm | 45.3 mm |
| 4 | 4.64 cm | 46.4 mm |
| 4.5 | 4.76 cm | 47.6 mm |
| 5 | 4.89 cm | 48.9 mm |
| 5.5 | 5.02 cm | 50.2 mm |
| 6 | 5.14 cm | 51.4 mm |
| 6.5 | 5.27 cm | 52.7 mm |
| 7 | 5.44 cm | 54.4 mm |
| 7.5 | 5.57 cm | 55.7 mm |
| 8 | 5.70 cm | 57.0 mm |
| 8.5 | 5.83 cm | 58.3 mm |
| 9 | 5.95 cm | 59.5 mm |
| 9.5 | 6.08 cm | 60.8 mm |
| 10 | 6.21 cm | 62.1 mm |
| 10.5 | 6.33 cm | 63.3 mm |
| 11 | 6.46 cm | 64.6 mm |
| 11.5 | 6.59 cm | 65.9 mm |
| 12 | 6.72 cm | 67.2 mm |
| 12.5 | 6.85 cm | 68.5 mm |
| 13 | 6.97 cm | 69.7 mm |
How to Measure Your Ring Size at Home (in CM)
Want to use a ring size chart in cm accurately? Follow these step-by-step methods for easy, reliable results.
✦ Method 1: Measure with a Strip of Paper or String
- Cut a thin strip of paper or string.
- Wrap it snugly around the base of the intended finger.
- Mark the point where the strip overlaps.
- Flatten and measure the length with a ruler (in centimeters).
- Match the length to the circumference values in the chart above.
💡 Tip: Measure at room temperature and in the evening, when your fingers are at their largest.
✦ Method 2: Measure an Existing Ring
- Place a ring that fits well on a ruler.
- Measure the inside diameter (not the outside) in millimeters.
- Use a conversion tool or chart to find the corresponding circumference and U.S. size.
Pro Tips for Getting the Most Accurate Fit
Even with a ring size chart in cm, small details can affect your comfort and fit. Here’s how to get the most accurate sizing:
- Measure multiple times at different times of day
- Avoid measuring after exercise or in cold weather
- Wider bands may need a slightly larger size
- Your dominant hand’s fingers tend to be larger
Still unsure? Book a professional sizing session with Vermont Gem Lab or visit us for in-person precision fitting.
When to Use CM-Based Ring Sizing
While most U.S. jewelers use standard numerical sizing (size 5, 6, 7, etc.), there are a few scenarios where using a ring size chart in cm is especially useful:
- International shopping or shipping
- Custom sizing from home
- Virtual consultations
- Lost or unknown ring sizes
- Planning a surprise gift
At Vermont Gem Lab, we often work with clients remotely. Our cm-based sizing process ensures that even from miles away, your ring will arrive perfectly tailored.
What If You’re Between Sizes?
If your circumference measurement falls between two sizes:
- Choose the larger size for wide rings
- Choose the smaller size if the band is narrow
- Ask us about quarter sizes or custom-fit inserts
We regularly craft rings in half and quarter sizes. Our team ensures that every ring fits your finger—and your lifestyle—with care and craftsmanship.
See Our Custom Ring Work
Looking for inspiration or ready to design your perfect-fit ring? Explore our custom ring gallery for examples of:
- Handcrafted engagement rings
- Custom men’s wedding bands
- Personalized birthstone and heirloom rings
- Platinum and gold fashion rings
- Engraved or gemstone-accented rings
Every ring is created with your measurements, preferences, and story in mind.
How Our Process Works
Whether you're working in inches, millimeters, or centimeters, our custom design process ensures a smooth experience:
- Consultation: In-person or virtual to discuss your sizing and design.
- Measurement: Use our printable chart or request a ring sizer.
- Sketching & Design: See your ideas visualized.
- Crafting: Our bench jewelers bring your piece to life.
- Final Fitting: Optional sizing check before delivery or shipping.
Why Choose Vermont Gem Lab for Custom Rings
We don’t just follow charts—we shape every piece of jewelry to suit you. That includes precision sizing, expert advice, and post-purchase care.
When you choose Vermont Gem Lab, you receive:
✅ Precision fit based on centimeters or inches
✅ Quarter-size availability and fit customizations
✅ Handmade rings from Vermont artisans
✅ Certified gemologist guidance
✅ Lifetime care and resizing support
Your jewelry should be as unique and comfortable as you are.
Final Thoughts: Find Your Ring Size with Confidence
Using a ring size chart in cm is a simple yet powerful step toward a custom ring you’ll love for life. Whether you’re gifting someone special, proposing, or marking your own milestone—getting the size right is the foundation of a perfect experience.
Let Vermont Gem Lab help you get it just right—with expert support, accurate tools, and craftsmanship you can feel.
👉 Start your custom ring journey today by visiting Vermont Gem Lab or scheduling a virtual sizing consultation.