Diamond education
Ring size guide
Get the size right before the ring is made.
By the CTJ Jewellery team, led by founder Greg Ward · Updated September 2026 · Editorial policy
Key facts
- Australian sizes use letters
- Free sizing in the showroom
- Measure the same finger
- Measure at the end of the day
- Wide bands fit tighter
- Resizing in about 3 to 7 business days
Australian ring size chart
Use this as a guide only. A professional sizing is more accurate.
| Size | Inside diameter | Circumference |
|---|---|---|
| H | 15.6 mm | 49.0 mm |
| J | 16.1 mm | 50.6 mm |
| L | 16.9 mm | 53.1 mm |
| N | 17.5 mm | 55.1 mm |
| P | 18.2 mm | 57.2 mm |
| R | 18.8 mm | 59.2 mm |
| T | 19.4 mm | 61.1 mm |
| V | 20.0 mm | 62.8 mm |
| X | 20.6 mm | 64.6 mm |
How to measure at home
- Wrap a thin paper strip around the base of the finger.
- Mark where it overlaps, keeping it snug but able to pass the knuckle.
- Measure the length in millimetres and match it to the circumference column.
- If you fall between sizes, choose the larger one.
Buying a surprise engagement ring?
Borrow a ring they wear on the same finger and bring it in, or trace its inside edge. We can size the ring before delivery, and resizing is quoted individually.