This is what I have found on the internet, other than this I am not sure:
Measurements for cones and spools
Nearly all of our cones and spools are wound on the same plastic core for uniformity. The dimensions for our thread cones and spools are below:
Standard Cone = 2,500 - 3,280 yds. depending on the thread line
Base Diameter = 2.5"
Height = 4"
Standard Spool = 600 - 1,420 yds. depending on the thread line
Base Diameter = 1.5"
Height = 2"