Calculate Lines Per Inch, Characters Per Inch

Tue, 06/11/2019 - 15:16 By Dave Brooks

Q: How do I determine the characters-per-inch and lines-per-inch settings to use in a Text print action?

A: You would calculate characters-per-inch using the following formula(s):

  • CPI = number of characters in a line to be printed / printable width in inches, or
  • CPI = number of characters / paper width - (left margin + right margin)

Calculate lines-per-inch using the following formula(s):

  • LPI = number of Lines to be printed on a page / printable height in inches, or
  • LPI = lines per page / paper height - (top margin + bottom margin)

Examples:

  1. I am printing on letter-size paper, landscape. I want 60 lines on each page, and there are 132 characters on each line. I've set the margins to 1/2 inch on all: top, bottom, left, and right.
    • CPI = 132 / (11 - (0.5 + 0.5)) = 13.20
    • LPI = 60 / (8.5 - (0.5 + 0.5)) = 8
  2. Printing again on letter size paper, portrait this time. I want 80 lines on each page, and there are 92 characters on each line. I've set the margins to .75 inches on top and bottom margins, 0.5 inches on the left and right margins.
    • CPI = 92 / (8.5 - (0.5 + 0.5)) = 12.2
    • LPI = 80 / (11 - (0.75 + 0.75)) = 7.6