Calculate pages per inch, book thickness, or page count from any two values, including caliper per sheet and spine width in multiple units.

Count printed sides: two pages per sheet. Thickness estimates cover the paper block only; binding, covers and compression can change the finished spine.

Pages Per Inch Formula

The following formula is used to calculate the pages per inch (PPI).

PPI = 2 / PT

Variables:

  • PPI is the pages per inch
  • PT is the caliper of one sheet of paper (inches)

To calculate printed pages per inch, divide 2 by the caliper of one sheet in inches: each sheet has two page sides. Dividing 1 by sheet caliper gives sheets per inch. You can also divide a known printed page count by its paper-block thickness. Covers and binding allowances are excluded.

What is Pages Per Inch?

Pages per inch (PPI) is a measure of the number of pages that fit into a one-inch stack. It is commonly used in the printing and publishing industries to estimate the thickness of books and documents based on the paper’s thickness. Understanding PPI is important for logistics, packaging, and ensuring that a book’s spine can accommodate the number of pages.

How to Calculate Pages Per Inch?

The following steps outline how to calculate the Pages Per Inch.

  1. First, determine the caliper of one sheet (PT) in inches.
  2. Next, use the formula PPI = 2 / PT.
  3. Finally, calculate the Pages Per Inch (PPI).
  4. After inserting the paper thickness and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

single-sheet caliper (PT) = 0.002 inches

Using PPI = 2 / PT, we find PPI = 2 / 0.002 = 1,000 printed pages per inch (500 sheets per inch).