In order to find your ring size, take a measuring tape and measure the circumference of your ring finger position.

There are several factors that affect ring size besides the actual finger measurement -
• The difference in size between finger joints and the position where a ring sits affects the choice of ring size.
• Fingers are not perfectly round.
• Fingers change size in response to body chemistry and temperature, sometimes by several sizes.
 
The size that is chosen is also affected by the specific ring. Wider rings and those in which a stone or setting projects toward the finger will require larger sizes than thinner rings, even for the same finger. Often, the best way to determine ring size is to go to a jeweller for a fitting.

Circumference Measurement

K  (50mm)
K½  (50.6mm)
L  (51.2mm)
L½  (51.9mm)
M  (52.5mm)
M½  (53.1mm)
N  (53.8mm)
O  (54.5mm)
O½  (60mm)