How to find a ring size for a surprise proposal
Borrow a ring she already wears on that finger and have it measured. It is the only method that measures the ring rather than guessing at the finger, and it is the one jewelers ask for. Everything else is a fallback.
Method 1: borrow a ring
Take one she wears on the intended finger, usually the left ring finger, but check, because sizes differ between fingers and between hands by as much as half a size.
A jeweler puts it on a sizing mandrel and reads it off in seconds. If you can get the ring to us or to any jeweler for ten minutes, you are done.
Borrow it in the evening if you can. Rings live in jewelry boxes overnight and get noticed in the morning.
Method 2: measure the inside diameter
If the ring cannot leave the house, measure it yourself. Lay it flat and measure the inside diameter across the widest point, in millimeters. Then match it:
| Inside diameter | US size |
|---|---|
| 15.7 mm | 5 |
| 16.5 mm | 6 |
| 17.3 mm | 7 |
| 18.1 mm | 8 |
| 19.0 mm | 9 |
Precision matters here: a full size is only 0.8 mm of diameter, so being half a millimeter out puts you most of a size wrong. Use a ruler with fine gradations, not a tape measure.
Method 3: ask someone who knows
A sister, a best friend, or her mother often knows already, or can go ring shopping with her and report back. This is usually the most accurate route after borrowing a ring, and the least risky, provided you pick someone who can genuinely keep it quiet.
Method 4: trace it
Stand the ring on paper and trace the inside circle carefully with a sharp pencil. Less accurate than a direct measurement, but better than a guess, and it takes thirty seconds.
What throws the measurement off
- Time of day. Fingers are largest in the evening and in the heat, smallest first thing and in the cold.
- Which hand. The dominant hand is usually slightly larger.
- Knuckles. If the knuckle is noticeably wider than the base of the finger, the ring has to clear the knuckle, size to that.
- Band width. A wider band fits more tightly at the same nominal size.
If you get it wrong
Most rings can be resized. A full eternity band cannot. The diamonds run the whole way around, so changing the size changes the number of stones. If you are proposing with an eternity band and you are unsure of the size, tell us before you order and we will talk it through.
For anything sized, our refund policy covers exchanges on eligible items within the returns window.
The short version
Borrow a ring from the correct finger. Get it measured properly. If you are between sizes, go up. A ring slightly loose can be worn on the day and adjusted after; one that will not pass the knuckle cannot.
Full conversion tables are in the size guide. If you would rather talk it through, email us or call +1 310-432-3658. We do this quietly and often.
