How do I calculate spine width?

Spine width depends on the number of pages and paper thickness. Paper thickness (in mm) can be roughly estimated as GSM x 0.001. Multiply by the number of sheets (leaves) for spine width.

How many sheets per signature?

A standard signature uses 4 sheets (folded to give 16 pages). Thicker paper may need 3 sheets per signature, while thin paper can use 5-6 sheets.

What board thickness for hardcover?

For A5-sized books, 1.5-2 mm greyboard is common. Larger books (A4+) typically use 2-3 mm board. Lightweight journals may use 1 mm board.

How much overhang should the cover have?

Standard overhang for case-bound books is 3 mm on the top, bottom and fore-edge. This protects the text block edges.

CraftCalcs

Bookbinding Calculator — Spine Width & Cover Dimensions

Calculate spine width, cover dimensions and page signatures for bookbinding projects.

Total Pages

Must be divisible by 4 for signatures

Page Width

Page Height

Paper Weight

Board Thickness

Greyboard thickness for covers

Binding Type

How We Calculate This

This calculator estimates bookbinding dimensions using standard ratios.

Spine Width

Calculated from page count and paper thickness. Paper thickness is estimated from GSM using the approximation: thickness (mm) = GSM x 0.001.

Cover Dimensions

For case binding, the cover adds a 3 mm overhang on three sides (fore-edge, top and bottom). Perfect binding and coptic stitch covers match the page size.

Signatures

Text blocks are divided into signatures (folded gatherings). Standard signatures use 4 nested sheets giving 16 pages. Saddle-stitched booklets use a single signature.

Frequently Asked Questions

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Last updated: 2025-02-20

All calculations are estimates. Always verify quantities before purchasing materials.