Determine Ring Size With a Ring Size Chart   Use a ring that fits you to determine your ring size. Place your ring over the nearest size circle. The inner edge of the ring should align with the outer edge of the circle. If your ring appears to fit between two sizes, buy the larger size.       Ring Size Chart (USA - Japan - British - German - Swiss)   You could take a piece of paper and wrap it around the finger you would like to size.  Hold the paper around your finger and mark where it fits around your entire finger.  Then measure the paper from one end to where the mark is.  The closest measurement to the chart size is your ring size.

Size (inches) Size (mm) Diameter (mm) U.S.A. size Japanese size British size German size Swiss size 1 14/16 48 15.27 4 1/2 8 I - 1/2 15 1/4 -- 1 15/16 49 15.70 5 9 J 1/2 15 3/4 -- 2 51 16.10 5 1/2 11 L 16 11 3/4 2 1/16 52 16.51 6 12 M 16 1/2 12 3/4 2 2/16 53 16.92 6 1/2 13 N 17 14 2 3/16 55 17.35 7 14 O 17 1/4 15 1/4 2 4/16 56 17.75 7 1/2 15 P 17 3/4 16 1/2 2 5/16 57 18.19 8 16 Q 18 17 3/4 2 6/16 58 18.53 8 1/2 17 Q 1/2 18 1/2 -- 2 7/16 59 18.89 9 18 R 1/2 19 -- 2 8/16 61 19.41 9 1/2 19 S 1/2 19 1/2 -- 2 9/16 62 19.84 10 20 T 1/2 20 -- 2 10/16 63 20.20 10 1/2 22 U 1/2 20 1/4 -- 2 11/16 65 20.68 11 23 V 1/2 20 3/4 -- 2 12/16 66 21.08 11 1/2 24 W 1/2 21 -- 2 13/16 68 21.49 12 25 Y 21 1/4 27 1/2 2 14/16 69 21.89 12 1/2 26 Z 21 3/4 28 3/4 2 15/16 70 22.33 13 27 -- 22 --