How to calculate spine width

The spine calculations are for most people a confusing element. For the most cases, our client will implement the calculations directly into their system. For that, we provide the formulas for the calculations.

Formula for spine width calculation


Spine in mm = (paperweight in gsm x paper bulk x (page count / 2)) / 1000 + (2 x cover thickness)


Spine in inch = ((paperweight in gsm x paper bulk x (page count / 2)) / 1000 + (2 x cover thickness)) / 25.4

The paper bulk values used by Cloudprinter is:

Paper type Bulk value
MCG 0.80
MCS 0.90
ECB 1.20
OFF 1.22

The cover thickness values used by Cloudprinter is:

Cover type Thickness in mm
Case Wrap / Hardcover - 3 mm material (default) 3.0
Case Wrap / Hardcover - 2 mm material 2.0
Perfect Binding / Softcover 0.5

Spine width calculator

We have made a guideline tool for you to easily calculate the spine based on the paperweight, paper type, and cover type.

You find the calculator here: Spine width calculator


This spine width calculation uses average bulk values. The characteristics of the paper used by different print partners may vary.

Case Wrap books mostly use pre-cut cardboard in the spine. The cardboard is therefore in a number of fixed sizes. These sizes may vary between print partners.