Enrichment · Passion Projects · Publishing

Pages times paper:
a spine and a cover
that fit.

Type the page count, trim size and paper. The calculator gives the spine width and the full cover canvas with bleed, so the title lands on the spine and not on the back cover.

Size the coverWhat you get

The spine width calculator

The worked example is made up: a 248-page class poetry anthology, 6 × 9 inches, on cream paper. Nothing you type leaves this browser.

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What you get

Enrichment · Passion ProjectsFree

What you finish with
Spine width, the full cover size with bleed in inches, millimetres and pixels at 300 dpi, the spine’s position on the canvas and the safe width for spine text. It prints as a summary and downloads as a spreadsheet.
Who it is for
Students publishing an anthology or yearbook, teachers running a publishing project, self-publishing writers and design students.
Format
Browser calculator for a phone, tablet or computer, by touch or keyboard. Prints a summary; downloads a spreadsheet (.csv); export and import a file.
Access
Free. No account, no sign-in and nothing to install. Everything you type stays in this browser; nothing is sent to Caveat.
Where it lives
The Passion Projects space in Caveat Enrichment.
Support
Questions, a correction or a request: team@caveatacademic.com.

How to use it

  1. Type the final page count, blank pages included.
  2. Choose the trim size.
  3. Choose the paper, or your printer’s pages per inch.
  4. Set your design canvas to the full cover size.
  5. Print the summary and keep it with the design file.

Size the cover

How the cover is sized

Thickness, then a wraparound.

The worked example: a 6 × 9 anthologySpine0.620 in248 × 0.0025 in+ two covers12.620 in6 + 6 in trim+ bleed12.870 in0.125 in each sideHeight9.25 in9 in + 2 × 0.125The worked example: a 6 × 9 anthologySpine0.620 in248 × 0.0025 in+ two covers12.620 in6 + 6 in trim+ bleed12.870 in0.125 in each sideHeight9.25 in9 in + 2 × 0.125
The spine is the paper’s thickness times the page count; the cover wraps back, spine and front with a little bleed all round.

The spine

Each page has a thickness, so the spine is the page count times that thickness. Printers publish it either as inches per page (cream paper is thicker than white) or as pages per inch, which is the same figure turned over. The spine grows quickly: 100 extra pages on cream add a quarter of an inch.

The wraparound

A paperback cover is one sheet: back cover, spine, front cover. Bleed is a margin of 0.125 inches past the trim on the outer edges, so colours that run off the edge still reach it after cutting. The fold can shift slightly, so keep spine text 0.0625 inches clear of each fold, and check the printer’s own cover template before you upload.

Sources

  1. Amazon Kindle Direct Publishing. Paperback cover calculator and templates: spine width by paper type, bleed (kdp.amazon.com/help).
  2. Amazon Kindle Direct Publishing. Paperback manuscript and cover formatting: page count and spine text guidance (kdp.amazon.com/help).
  3. The Chicago Manual of Style (18th ed., 2024). Chapter 1, Books and journals: parts of a book and printing terms.
  4. National Institute of Standards and Technology. The inch defined as exactly 25.4 millimetres (nist.gov).

The worked example is made up. Printers revise their paper specifications; always confirm with the printer’s template. Your figures stay in this browser. Support: team@caveatacademic.com.