What is the average ring size for women?

6.5. That's the number most sources quote for women in the United States, and I've been muttering about it at the bench for years because it tells you almost nothing about the finger sitting across from me.

Most women land between a 5 and an 8. Size 6 and 7 are the two I order most. But your finger is not a static object. It swells in summer heat, in the early morning, after a salty dinner, and for a dozen other reasons you don't control. I've measured the same finger at a 6.25 in January and a 7 in August.

Last July a client named Nicole came in convinced she was a size 6 because a chain-store salesperson had measured her once, in air conditioning. The ring fit at noon. By five o'clock she couldn't get it past her knuckle. We resized to a 6.75 and she's worn it every day since.

If you're buying a surprise ring and you have nothing else to go on, 6.5 is a reasonable blind guess. A better move is to trace one of her existing rings on paper and bring it in, or ask her best friend to check the inside of a ring she wears on that finger. The friend won't keep the secret. That's fine. At least you'll start closer.

For a custom ring, I won't cut metal until I've measured the same finger twice on the same day, once cool and once warm. Fingers lie. Measure anyway.