The measurement found on the chart is your correct ring size. Simply print out an accurate ring size chart and place a ring that currently fits you on each circle of the chart until you find a circle that matches perfectly with the ring's circumference. Place a ring that currently fits you on a ring sizing chart (click on an image to download).
If two sizes seem to match, you should go with the bigger one. Simply place the sizer around the base of your finger. Whatever size you decide on, the results are sure to be accurate. That said, your ring sizer can either be a key ring with a wide range of other rings attached to it, or it can be a measuring tape. So if you excessively stretch them when measuring your ring finger, your ring size can end up being smaller than expected. You should also note that a floss and a string are materials that stretch. Pick the closest measurement on the ring size chart to find your ring size.
With that done, note down its measurement in millimeters (this measurement will be your ring inside circumference!).
