Ring Size Guide
Measure once at home and order with confidence — our rings come in US and European sizes.
How to choose your ring size
Choosing the correct ring size is simple with a strip of paper and a ruler. Measure your finger carefully before ordering, and your ring will sit comfortably from the first day.
- Wrap a strip of paper around the base of your finger, snug but not tight.
- Mark where the ends meet and measure the strip in millimetres — that is your finger’s circumference.
- Match the number to the charts below to find your US or European size.
US ring sizes
The US system uses numbered sizes, typically from 3 to 13 for women, in half-size steps (for example 6, 6.5, 7).
| US size | Circumference (mm) | Diameter (mm) |
|---|---|---|
| 5 | 49.3 | 15.7 |
| 6 | 51.9 | 16.5 |
| 7 | 54.4 | 17.3 |
| 8 | 57.0 | 18.1 |
| 9 | 59.5 | 18.9 |
| 10 | 62.1 | 19.8 |
European ring sizes
The European system sizes a ring by its inner circumference in millimetres — an EU size 54 ring fits a finger measuring 54 mm around. This makes conversion straightforward: your measured circumference in millimetres is your EU size.
| EU size | Circumference (mm) | US size (approx.) |
|---|---|---|
| 49 | 49.0 | 4.75 |
| 52 | 52.0 | 6 |
| 54 | 54.0 | 6.75 |
| 57 | 57.0 | 8 |
| 59 | 59.0 | 8.75 |
| 62 | 62.0 | 10 |
Measurement tips
- Measure your finger at the end of the day, when it is at its largest.
- Avoid measuring when your hands are cold — cold fingers are narrower.
- Make sure the paper strip slides over your knuckle but does not spin on your finger.
- If you are between two sizes, choose the larger one.
- Measure the finger you will wear the ring on — your dominant hand is often slightly larger.
Fingers change size
Finger size can change with temperature and time of day. Fingers tend to be larger in the evening and in warm weather, and narrower in the morning or in the cold. For the most accurate result, measure at a neutral time of day and at room temperature.
Most of our rings are adjustable — check the product page, or write to care@lumera.com if you need help choosing.
