Ring Size Guide

Find Your Perfect Fit

At STDIAM, we believe elegance begins with precision. A flawless ring deserves a perfect fit. Use our signature guide to confidently determine your size for a piece that is purely sustainable and uniquely yours.

STDIAM Premium Precision Fit Guide Tools and Ring

How to Measure At Home

Method 1: Measure an Existing Ring

This is the most accurate method if you already own a ring that fits the exact same finger perfectly.

  1. Select a ring that fits comfortably on the desired finger.
  2. Place the ring over a reliable ruler.
  3. Measure the Inside Diameter in millimeters (mm). Ensure you are measuring the straight line straight across the center of the inner circle. Do not include the metal width.
  4. Match this measurement to the 'Inside Diameter' column in our chart.
Measuring inside diameter of a ring
Measuring finger circumference

Method 2: Measure Your Finger

If you do not have an existing ring, you can easily measure your finger using common household items.

  1. Cut a thin strip of non-stretchy paper or a piece of string.
  2. Wrap it snugly around the base of the finger you intend to wear the ring on.
  3. Use a pen or pencil to mark the exact point where the paper or string overlaps to form a complete circle.
  4. Unwrap it and measure the length from the starting end to your mark in millimeters (mm). This is your Inside Circumference.

International Ring Size Chart Global Conversions

Use the precise conversion chart below to find your local equivalent. Slide the table horizontally to view all countries. If you measure between two sizes, we recommend selecting the larger size.

INSIDE CIRCUMFERENCE
IN
MM
 US, Canada,
Mexico		 UK, Australia, Ireland,
New Zealand, South Africa		 France Germany, Russia,
Ukraine, Asia		 India, China, Japan, South
America, Turkey, Israel		 Italy, Spain, Netherlands,
Switzerland
1.84
46.8
 4 H 47 15 7 6 1/2
1.89
48.0
 4.5 I 48 15 1/4 8 7 3/4
1.94
49.3
 5 J 1/2 49 15 3/4 9 9
1.99
50.6
 5.5 K 1/2 50.5 16 1/4 10 10 1/4
2.04
51.9
 6 L 1/2 52 16 1/2 12 11 1/2
2.09
53.1
 6.5 M 1/2 53 17 13 12 3/4
2.14
54.4
 7 N 1/2 54.5 17 1/4 14 14
2.19
55.7
 7.5 O 1/2 56 17 3/4 15 15 1/4
2.24
57.0
 8 P 1/2 57 18 16 16 1/2
2.29
58.3
 8.5 Q 1/2 58.5 18 1/2 17 17 3/4
2.34
59.5
 9 R 1/2 59.5 19 18 19
2.39
60.8
 9.5 S 1/2 61 19 1/2 19 20 1/4
2.44
62.1
 10 T 1/2 62.5 20 20 21 1/2
2.49
63.4
 10.5 U 1/2 63.5 20 1/4 21 22 3/4
2.54
64.6
 11 V 1/2 65 20 3/4 22 24

Pro Tips for the Perfect Fit

  • Fingers Change Size: Your finger size fluctuates slightly throughout the day based on temperature, humidity, and activity. For the most accurate measurement, measure your finger at the end of the day when it is warm. Avoid measuring when your hands are cold.
  • Knuckle vs. Base: If your knuckle is significantly larger than the base of your finger, measure both areas. Choose a size that is in between the two measurements, ensuring the ring can slide over the knuckle comfortably but won't be too loose at the base.
  • Band Width Matters: Wider ring bands (generally over 5mm) tend to feel tighter than delicate, thin bands. If you are purchasing a wide band design, we recommend sizing up by one half size (e.g., from a US 7 to a US 7.5).

Free Ring Resizing

If you order a ring and love it, but didn't quite get the ring size right, don't worry! We are happy to resize your ring one time for FREE within 30 days after purchase. It's simple: Ship the ring to us and we'll ship it back. If we determine that we are unable to size the ring up or down to the new size, we will inform you and give you an option to either place a special order for the size required or have it shipped back to you as it is.

Still Unsure About Your Size?

Our concierge team is dedicated to ensuring your STDIAM experience is flawless. If you require expert assistance or personalized advice on selecting the right fit, especially for gifts, please contact us.

Contact Our Concierge