U.S. ring sizes follow a scale of numbers (and half numbers).- Typically from ring size 3 to 13.5 for adults. Women’s rings are commonly between sizes 3 and 9, while men’s rings are usually sized between 8 and 14. Those units match up to your finger’s width in millimeters.

- There are three common and easy ways to measure your ring size at home—using string, a ring size chart, and a ring sizer—so you can get the right piece of jewelry.

- There are easy way to measure your ring size at home, use string or floss to measure your finger.- You can measure your ring size using either string or, perhaps a more common item in your home, floss. - Take one of these measurement tools and wrap it around the base of your finger, marking where the string or floss first overlaps with a pen. Then, line that up with a ruler and take down its length in millimeters.- With standard ring sizes, every half-size matches up to a 0.4 millimeter increment, starting with size 3 equaling 14 mm, size 3.5 equal to 14.4 mm, size 4 equal to 14.8 mm, and so on.

Note:

- Your ring should fit your finger comfortably, snug enough so that it will not fall off, but loose enough to slide over your knuckle with some resistance.