Ring Size Guide
Find your perfect fit for diamond engagement rings, eternity bands, and bespoke fine jewelry with our comprehensive size chart and measurement instructions.
Measure An Existing Ring
- Select a ring that currently fits the desired finger comfortably.
- Measure the inside diameter (inner edge to inner edge in mm) using a precise ruler or caliper.
- Compare your measurement against the Inside Diameter column in our chart below to find your exact US size.
Measure Your Finger
- Wrap a strip of paper or string snugly around the base of your finger.
- Mark the point where the paper meets with a pen.
- Measure the length of the paper strip in millimeters (mm) to get your circumference and match it to our chart.
International Ring Size Conversion Chart
| US / Canada | Inside Diameter (mm) | Inside Circumference (mm) | UK / Australia | EU / Germany |
|---|---|---|---|---|
| 3 | 14.1 mm | 44.2 mm | F | 44 |
| 3.5 | 14.5 mm | 45.5 mm | G | 45 |
| 4 | 14.9 mm | 46.8 mm | H | 47 |
| 4.5 | 15.3 mm | 48.0 mm | I | 48 |
| 5 | 15.7 mm | 49.3 mm | J 1/2 | 49 |
| 5.5 | 16.1 mm | 50.6 mm | L | 51 |
| 6 | 16.5 mm | 51.9 mm | M | 52 |
| 6.5 | 16.9 mm | 53.1 mm | N | 53 |
| 7 | 17.3 mm | 54.4 mm | O | 54 |
| 7.5 | 17.7 mm | 55.7 mm | P | 56 |
| 8 | 18.1 mm | 57.0 mm | Q | 57 |
| 8.5 | 18.5 mm | 58.3 mm | Q 1/2 | 58 |
| 9 | 19.0 mm | 59.5 mm | R 1/2 | 60 |
| 9.5 | 19.4 mm | 60.8 mm | S 1/2 | 61 |
| 10 | 19.8 mm | 62.1 mm | T 1/2 | 62 |
Expert Sizing Advice
- Temperature Matters: Fingers expand in warm temperatures and shrink in cold weather. Always measure when your hands are at room temperature.
- Knuckle Clearance: If your knuckle is significantly larger than the base of your finger, choose a size in between the two measurements.
- Wider Bands Fit Tighter: If you are purchasing an eternity band wider than 4mm, we recommend selecting half a size larger.
- Complimentary Resizing: All Bloomer Diamonds engagement rings include one complimentary ring resizing within the first 60 days of purchase.
FAQS
Yes. Every center diamond is accompanied by an official grading certificate from internationally recognized gemological laboratories (such as IGI or GIA) verifying its 4Cs: Cut, Color, Clarity, and Carat weight.
We offer a 30-day hassle-free return and exchange policy on all unworn fine jewelry pieces in their original presentation packaging. We provide a prepaid, fully insured shipping label for safe handling.
Our lifetime warranty covers all manufacturing defects and includes complimentary prong inspections, stone tightening, professional ultrasonic cleaning, and rhodium replating of your gold and platinum jewelry.
You can refer to our interactive Ring Size Guide to measure an existing ring or your finger. We also offer one complimentary ring resizing within 60 days of purchase.
Every order is shipped in discreet, unbranded tamper-evident luxury packaging and is 100% fully insured from our atelier to your doorstep. Direct adult signature is required upon delivery.
