OurCoordinates
Ring Size Chart
All OurCoordinates rings are listed in whole US sizes. Coordinates bands run 5–10; men's rings run to 12. Find your size below, then choose it on the product page — every ring is engraved to order, so it cannot be resized after it is cut.
| US size | Inside diameter | Inside circumference |
|---|---|---|
| 5 | 15.7 mm | 49.3 mm |
| 6 | 16.5 mm | 51.9 mm |
| 7 | 17.3 mm | 54.4 mm |
| 8 | 18.1 mm | 57.0 mm |
| 9 | 18.9 mm | 59.5 mm |
| 10 | 19.8 mm | 62.1 mm |
| 11 | 20.6 mm | 64.6 mm |
| 12 | 21.4 mm | 67.2 mm |
How to measure at home
With paper: wrap a strip of paper snugly around the base of the finger, mark where it overlaps, then measure the marked length in millimetres. That is your inside circumference — match it in the table above.
With a ring you already own: measure the inside diameter across the widest point in millimetres and match it to the diameter column.
Three things that change the answer
- Time of day. Fingers are largest at the end of the day and smallest in the cold. Measure in the evening, at room temperature.
- Band width. Wide bands sit more snugly. On our 6 mm coordinates band, size up if you are between sizes; on the 4 mm, stay put.
- Knuckle size. The ring has to pass the knuckle. If your knuckle is noticeably larger than the base of the finger, size to the knuckle.
Buying as a surprise? Borrow a ring they already wear on the same finger and measure its inside diameter — or choose an adjustable bracelet instead. Email info@ourcoordinates.com and we will help.
See also: full size guide (necklace lengths and bracelet fit) · shop rings · engraving guide