Ring Size Guide
Ring size guide
MOOI rings use HK sizes 9 to 20. Seri and Purnama also come in a free size (an open band you adjust by hand). Between two sizes, take the larger one. Still unsure? DM @mooimooi.jewellery a photo of a ring you already own and we will size you from it.
1. String or paper strip
- Wrap a non-stretch string or a 2 to 3 mm paper strip around the base of the finger.
- Mark where it overlaps. Snug, not tight.
- Measure the length in millimetres with a ruler. That is your circumference. Divide by 3.14 for the diameter.
- Compare with the table below.
Measure at room temperature, in the evening if you can (fingers are slightly bigger by evening), and not straight after exercise.
2. A ring you already own
Measure the inside diameter of a ring that fits the same finger, edge to edge in millimetres, and read it off the table.
HK size table
| HK size | Inner diameter (mm) | Circumference (mm) |
| 6 | 14.1 | 44.3 |
| 7 | 14.5 | 45.5 |
| 8 | 14.8 | 46.6 |
| 9 | 15.2 | 47.7 |
| 10 | 15.5 | 48.7 |
| 11 | 15.9 | 49.9 |
| 12 | 16.2 | 50.9 |
| 13 | 16.6 | 52.1 |
| 14 | 16.9 | 53.1 |
| 15 | 17.3 | 54.3 |
| 16 | 17.7 | 55.6 |
| 17 | 18.0 | 56.5 |
| 18 | 18.3 | 57.5 |
| 19 | 18.7 | 58.7 |
| 20 | 19.0 | 59.7 |
| 21 | 19.4 | 60.9 |
| 22 | 19.7 | 61.9 |
| 23 | 20.1 | 63.1 |
| 24 | 20.4 | 64.1 |
| 25 | 20.8 | 65.3 |
Finger shape
- Tapered fingers (narrower at the tip): size for the base, but make sure the ring passes over the knuckle.
- Wider knuckles: size for the knuckle and accept a little looseness at the base, or choose the free size.
Common mistakes
- Measuring with thick string or ribbon adds 1 to 2 sizes.
- Ignoring the knuckle gives a ring that will not go on.
- Fingers swell by 3 to 5% in the evening and on long flights; measure in the evening for a fit that works all day.
Wrong size after all? Return the unworn piece within 14 days for a full refund and re-order in the right size; we prioritise the remake. Details on the Return and Exchange page.