Find your ring size from a finger measurement, by entering the inner diameter of a ring that already fits or the finger's circumference, both in millimeters.
How to measure
Inner diameter: measure the distance across the hole of a ring that already fits well. Circumference: wrap a strip of paper or string around your finger, mark where it overlaps, and measure that length with a ruler.
Reference table (diameter/circumference → size)
| Circumference (mm) | BR size | US | EU (approx.) |
|---|---|---|---|
| 44.3 | 8 | 3.5 | 44 |
| 46.8 | 10 | 4.5 | 47 |
| 49.3 | 12 | 5.5 | 49 |
| 51.9 | 14 | 6.5 | 52 |
| 54.4 | 16 | 7.5 | 54 |
| 56.9 | 18 | 8.5 | 57 |
| 59.5 | 20 | 9.5 | 60 |
| 62.0 | 22 | 10.5 | 62 |
| 64.7 | 24 | 11.5 | 65 |
| 66.0 | 25 | 12 | 66 |
| 68.5 | 27 | 13 | 69 |
Why the measurement can vary during the day
Fingers swell slightly with heat, physical activity and over the course of the day — measure preferably at night, at a normal hand temperature, for a more reliable result.
Frequently asked questions
Do I need to enter both diameter and circumference?
No — just enter one of the two. If you enter diameter, circumference is computed automatically (circumference = diameter × π), and vice versa.
Is the EU size shown exact?
It is an approximation — European numbering usually corresponds directly to the inner circumference in millimeters, so we use the rounded value.
Will the ring fit perfectly with this result?
It is a good reference, but the safest way is to try the ring on physically or use a jeweler's ring sizer, since band width and shape also affect fit.