When choosing what size ring to purchase and wear, it is best to measure the finger with an actual ring sizing tool.  This way you can find the exact fit for your finger.

However, that is not always possible and so you must resort to other methods to determine your finger ring size.   One way to do this is to take a measuring tape or piece of string and wrap it around your finger and note the distance around your finger by reading the measurement on the measuring tape or measuring the length of string that wrapped around.  This distance is the length around your finger or the circumference of the ring.  You can refer to the chart below and determine which ring to order.  When doing this, make sure the tape or string is snug but not pinching or squeezing your finger.  This way you ensure the ring will fit over your finger.  If pinching or squeezing, you run the risk of the ring being too small to fit over your knuckle. 

If the ring circumference is between the ring sizes, it is usually safer to choose the larger size up for your ring choice.

Also, remember that your fingers will swell or shrink due to different conditions such as the weather, so please keep this in mind when determining your ring size.

Ring Size and Dimension Table

Here are the common ring dimensions from ring sizes 4 to 14

Ring Size	Ring Circumference or Length in millimeters (mm)	Ring Inside Diameter in millimeters (mm)
4	46.8	14.90
4 1/2	48	15.29
5	49.3	15.70
5 1/2	50.6	16.11
6	51.9	16.53
6 1/2	53.1	16.91
7	54.4	17.32
7 1/2	55.7	17.74
8	57	18.15
8 1/2	58.3	18.57
9	59.5	18.95
9 1/2	60.8	19.36
10	62.1	19.78
10 1/2	63.4	20.19
11	64.6	20.57
11 1/2	65.9	20.99
12	67.2	21.40
12 1/2	68.5	21.82
13	69.8	22.23
13 1/2	71.1	22.64
14	72.4	23.06
14 1/2	73.7	23.47

 

Wider Band Ring Sizing

Wider band rings should be sized larger to accommodate the wider band width to fit over the knuckle of the finger since these fit more snug than thinner bands.  For every two millimeters increase in width, the ring should increase by a quarter size.  Most rings, less than 4 mm in width, can be sized normally and not need to be increased in size except for small sized rings.

For example, a person wearing a size 8 ring with a 4 mm wide band and wanted to wear a 8 mm wide band would need to choose a size 8 1/2 ring to fit comfortably on their finger.