Method 1: This is a chart that will be extremely helpful for you to determine the ring size that you need. You can either make use of tape or a small piece of string to measure the area that will be occupied by the ring. When it becomes a complete circle, make a mark on such a string. This will be helpful for you to compare with the chart that is mentioned below. For extra width, you can add another size to accommodate.
Step 1: Wrap a string, piece of paper, or fabric around the base of the finger on which you plan to wear your ring
Step 2: Make sure the string is snug, but not tight; mark the spot where it overlaps
Step 3: Measure the string in MM and input the measurement below
Method 2: Here is another chart that can also be considered in determining the appropriate ring size. It measures inside the diameter of such ring in millimeters. This is normally used for double checking your results from the usual paper method. Apart from this, you can also make use of the ring that you wear daily and cross check the same with below chart.
Step 1: Take a finger ring, place it on the scale. Step 2: Measure the inner diameter. Step 3: Use the following chart to determine your ring size.