A simple tool to measure your finger in order to get the perfect ring size.
15 sizes in total (Size 3.5 - Size 10 in .5 increments)
US, Canada, Mexico: ring_inside_circumference = 36.5 mm + 2.55 mm × ring_size
US, Canada, Mexico: ring_diameter = 11.63 mm + 0.8128 mm × ring_size
All measurements based on this chart: https://en.wikipedia.org/wiki/Ring_size