Size Guide
Find Your Perfect Ring Size
Finding the right ring size is not only about measuring your finger. The ring’s width and profile also affect how it feels and fits.
Below, you’ll find sizing information specifically for Singularity carbon rings, along with general guidance for wearing flat-profile and wider bands.
Read the guide from beginning to end, or jump directly to the section you need:
Ring Size Chart
Our rings are made in standard EU sizes.
Use the conversion chart below to find the corresponding US, UK, Japanese, French and Italian ring size.
The chart also includes the ring’s inner diameter in millimetres. This is the most reliable reference when comparing different international sizing systems.
Choosing the Right Size for a Flat Ring
Singularity carbon rings have a flat inner profile. This creates their clean, modern shape, but it also means that the correct size may be slightly larger than the size you would wear in a thin, rounded ring.
Flat rings cover more of the finger and do not slide over the knuckle as easily as narrow rings with a rounded profile. The wider the ring, the more space it usually needs. This is not specific to carbon fibre. The same sizing principle applies to any wide or flat-profile ring, including metal wedding bands.
1. Measuring with a Flat Ring or Flat Ring Sizer
If you are measuring with a flat-profile ring or flat ring sizer, such as our ring sizing set, and your new ring will have a similar width, choose the size you measured.
Flat profile and similar width = keep the measured size
2. Measuring with a Thin or Rounded Ring
If your reference ring or ring sizer is thin and has a rounded profile, add one EU size when choosing a flat ring approximately 2–4 mm wide.
Thin, rounded ring → 2–4 mm flat ring = add one size
3. Choosing a Wide Ring
Wider rings cover more of the finger and therefore need additional space for comfortable movement, natural changes in finger size and mild swelling throughout the day.
When choosing a flat ring approximately 5–10 mm wide based on a thin or rounded reference ring, add two EU sizes in total. Yes, a wide ring may genuinely need to be up to two sizes larger than a thin ring worn on the same finger.
Thin, rounded ring → 5–10 mm flat ring = add two sizes
If you already have a 2–4 mm flat-profile ring and would like a wider model, add one EU size for comfortable wear.
2–4 mm flat ring → 5–10 mm flat ring = add one size
Printable Ring Size Tool
You can use our printable PDF guide to measure the inner diameter of a ring you already own.
Choose a ring that fits the finger on which you plan to wear your new ring. Place it over the printed circles and find the circle that fits precisely inside the ring. The black printed line should remain just visible around the entire inner edge of your ring. It should not be hidden underneath the ring.
Once you have found the measured size, follow the recommendations in the Choosing the Right Size for a Flat Ring section above.
Before Measuring
The document is designed for A4 paper and must be printed at 100% or Actual Size.
After printing, measure the 1 cm reference line with a ruler to confirm that the document has been printed at the correct scale.
Alternative Measuring Methods
Let’s be honest: some commonly recommended measuring methods are not precise enough for ordering a ring.
String or cord
We do not recommend it. String can stretch, twist or tighten around the finger, producing highly inaccurate results.
A strip of paper
This may give you a very rough estimate, but small differences in tension or marking can easily change the measured size.
Plastic ring-sizer tapes
These work in a similar way to a paper strip. They can be useful for getting a general idea of the sizes of several fingers, but they are not always accurate enough when choosing a precise size for one particular finger.
Phone or tablet measuring apps
We do not recommend them. Screen calibration and the way the ring is positioned can affect the result. We have tested several apps ourselves and did not find them consistently reliable.
For the most accurate result, we recommend measuring:
With a flat ring sizer.
or
At a professional jewellery store — ask to try on a ring with a similar width and profile to the one you plan to purchase.
or
Using the exact inner diameter of a ring that already fits you well.