ICO Column widths in inches (approximate)

 1 column (9.5 picas) 1 9/16" (1.58")
 2 columns (20 picas) 3 5/16" (3.33")
 3 columns (30.5 picas) 5 1/16" (5.08")
 4 columns (41 picas) 6 13/16" (6.83")
 5 columns (51.5 picas) 8 9/16" (8.58")
 6 columns (62 picas) 10 5/16" (10.33")