Ring Size Guide: How to Find Your Ring Size
Last updated: November 4, 2026
The right ring size matters, especially for an engagement ring or an eternity band, which cannot be resized easily. Use the ring size chart below and one of three simple ways to find your ring size at home. The average women’s ring size in the U.S. is about a 6.
U.S. ring size chart (mm and inches)
| U.S. ring size | Inside diameter | Inside circumference |
|---|---|---|
| 4 | 14.9 mm (0.59 in) | 46.8 mm (1.84 in) |
| 4.5 | 15.3 mm (0.60 in) | 48.0 mm (1.89 in) |
| 5 | 15.7 mm (0.62 in) | 49.3 mm (1.94 in) |
| 5.5 | 16.1 mm (0.63 in) | 50.6 mm (1.99 in) |
| 6 | 16.5 mm (0.65 in) | 51.9 mm (2.04 in) |
| 6.5 | 16.9 mm (0.67 in) | 53.1 mm (2.09 in) |
| 7 | 17.3 mm (0.68 in) | 54.4 mm (2.14 in) |
| 7.5 | 17.7 mm (0.70 in) | 55.7 mm (2.19 in) |
| 8 | 18.1 mm (0.71 in) | 57.0 mm (2.24 in) |
| 8.5 | 18.5 mm (0.73 in) | 58.3 mm (2.30 in) |
| 9 | 19.0 mm (0.75 in) | 59.5 mm (2.34 in) |
| 9.5 | 19.4 mm (0.76 in) | 60.8 mm (2.39 in) |
| 10 | 19.8 mm (0.78 in) | 62.1 mm (2.44 in) |
Our rings are offered in U.S. sizes 4 to 8.5. Need another size? Contact us.
How to find your ring size at home
1. Measure a ring that already fits
Take a ring that fits the right finger and measure the inside diameter, edge to edge, in millimeters. Find the closest number in the “inside diameter” column above. This is the most accurate way to find a ring size without a ring sizer.
2. Use a strip of paper or string
- Wrap a thin strip of paper or a piece of string around the base of your finger.
- Mark the point where it overlaps.
- Lay it flat and measure the length in millimeters.
- Find the closest number in the “inside circumference” column.
3. Use a measuring tape
A soft sewing measuring tape works the same way as the paper strip: wrap it around the base of the finger, read the circumference in millimeters, and match it to the chart.
Tips for an accurate ring size
- Measure at the end of the day, when your fingers are at their largest, and not when your hands are cold.
- The ring has to pass over your knuckle. If your knuckle is much wider than the base of your finger, choose the size between the two.
- Between two sizes? Choose the larger one.
- Wide bands (over about 4 mm) fit tighter: go up a quarter to a half size.
- Eternity bands have diamonds all the way around and can’t be resized easily, so be sure of the size before you order an eternity band.
How to find her ring size secretly
Planning a surprise proposal? Try one of these:
- Borrow a ring she wears on her ring finger (left hand, fourth finger) and measure it as in method 1. Put it back quickly.
- Press the ring into a bar of soap or trace the inside on paper, then measure the diameter.
- Ask a close friend or family member who may know her size.
- If you are unsure, choose a ring that can be resized later; avoid full eternity bands for a surprise.
Ready? Browse diamond engagement rings or see our gift guide for Christmas and Valentine’s Day order-by dates.
Lifetime resizing and polishing
We offer complimentary lifetime resizing and polishing on all jewelry and rings purchased from us. Please note that if a resizing requires additional gold or gemstone work, the customer will be responsible for the cost of the added materials. Full eternity bands are the exception: they usually can’t be resized, so check the size first.
Get measured in Bolingbrook
Visit our showroom at The Promenade Bolingbrook to try rings on and check your size in person. Walk-ins are welcome Tuesday to Sunday, 12–6 PM. Get directions.
Contact us
Arra Jewels
639 E Boughton Rd, Suite 175 (The Promenade Bolingbrook)
Bolingbrook, IL 60440
Phone: (224) 806-6786
Email: contact@arrajewelsusa.com