How to find your ring size 1st Way Take a ring that fits you well and measure in millimeters (mm) the inside part (diameter) of the ring, using a ruler.Match the millimeters with the table below. 2nd Way Wrap a thread or a measuring tape loosely around your finger.Mark with a pen the end of the thread (or the tape).Put the thread on a line and measure it’s length with the help of a ruler. Again match the millimeters you found with the sizes below. Cirmumfence (mm) Diameter(mm) Our size diagram Our suggestion 42.92 13.67 43 Pinky finger 44.17 14.07 44 45.46 14.48 45 46 14.65 46 46.72 14.88 47 48.01 15.29 48 48.35 15.4 49 49.61 15.8 50 Ring finger 50.54 16.1 51 51.84 16.51 52 52.81 16.82 53 53.69 17.1 54 Average female size 54.47 17.35 55 55.73 17.75 56 57.11 18.19 57 58.18 18.53 58 59.31 18.89 59 Index finger 59.97 19.1 60 60.94 19.41 61 62.29 19.84 62 Large female size 63.42 20.2 63