Ring Size Converter
Convert ring diameter and circumference to ring size
Enter the inside diameter of a ring or the inside circumference around a finger to estimate US, UK and EU ring sizes for online jewelry shopping.
Enter ring measurement
Measure the inside diameter of a ring that fits, or measure finger circumference with a strip of paper.
Result
Approx US ring size
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Approx UK and EU sizes
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Diameter
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Circumference
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Sizing note
Enter a ring measurement to see a practical sizing note.
Common ring size examples
| US size | Approx UK size | Approx EU size | Inside diameter | Inside circumference |
|---|---|---|---|---|
| US 5 | UK J½ | EU 49 | 15.7 mm | 49.3 mm |
| US 6 | UK L½ | EU 52 | 16.5 mm | 51.9 mm |
| US 7 | UK N½ | EU 54 | 17.3 mm | 54.4 mm |
| US 8 | UK P½ | EU 57 | 18.1 mm | 57.0 mm |
| US 9 | UK R½ | EU 59 | 18.9 mm | 59.5 mm |
| US 10 | UK T½ | EU 62 | 19.8 mm | 62.1 mm |
How it helps
Choose a ring size before ordering online
Ring sizes can be shown as US numbers, UK letters or EU millimeter sizes. This converter helps compare common systems from a diameter or circumference measurement.
For important rings, measure more than once, avoid measuring when fingers are cold or swollen, and confirm the jeweler’s own size chart before ordering.
FAQ
Ring size converter questions
What does the ring size converter do?
This ring size converter estimates ring size from inside diameter or inside circumference and shows approximate US, UK and EU sizes.
Should I measure ring diameter or finger circumference?
Both can work. Measuring the inside diameter of a ring that already fits is often easier, while measuring finger circumference can help when you do not have a ring available.
Are ring size conversions exact?
No. Ring size conversions are approximate because charts vary slightly by jeweler and country. Use a professional ring sizer for important purchases.
What does EU ring size mean?
EU ring size is commonly based on the inner circumference in millimeters. For example, a ring circumference around 54 mm is close to EU size 54.
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