Knowledge Centre
Ring Size Guide
Lucky Jewellery uses UK ring sizing as the primary reference, with US, EU, China and Hong Kong comparisons, plus internal diameter and circumference in millimetres.
Conversion tool
Convert your ring size
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How to measure
Measuring your finger and existing rings
How to measure an existing ring
- Place a ring that fits comfortably on a flat surface.
- Measure the inside diameter across the widest point in millimetres.
- Compare the diameter with the conversion chart above.
How to measure your finger
- Wrap a thin strip of paper around the base of your finger.
- Mark where the paper overlaps and measure the length in millimetres — that is the circumference.
- Divide the circumference by π (3.14159) for the inner diameter.
Band width, temperature and time of day
- • Wide bands fit tighter than narrow bands at the same nominal size.
- • Fingers swell in warm weather and shrink in cold.
- • Measure late afternoon for a balanced size.
When to request professional sizing
For valuable, custom-made or non-resizable rings, please confirm the final size with Lucky Jewellery or a qualified jeweller before ordering.