How to use this calculator

1. Select your paper type: white, cream or premium color.
2. Enter your page count.
3. Enter your trim width and height in inches, for example 6 x 9.

You get the spine width in inches and millimeters, plus the full cover width and height including bleed.

How spine width is calculated

Spine width equals page count multiplied by the paper thickness per page. KDP’s published thickness values are about 0.002252 inches per page for white paper, 0.0025 for cream paper and 0.002347 for premium color.

Full cover width equals two times the trim width, plus the spine width, plus 0.25 inches of bleed. Full cover height equals the trim height plus 0.25 inches.

Example: A 120-page, 6 x 9 inch book on white paper has a spine of about 0.270 inches. The full cover is about 12.52 inches wide and 9.25 inches tall.

Cover design tips

• Keep important text and logos away from the edges and the spine fold.
• KDP recommends adding spine text only on books with enough pages. About 79 pages is the commonly used minimum.
• Always download KDP’s cover template for your final check, because it is the official reference.
• If you change page count or paper type later, recalculate the spine.

Related tools: [Royalty Calculator], [Book Title Ideas].

FAQ

How do I calculate spine width for KDP?

Multiply your page count by the paper thickness: 0.002252 for white, 0.0025 for cream, 0.002347 for premium color.

What is bleed on a KDP cover?

Bleed is extra image area that extends past the trim edge so no white edges show after cutting. KDP uses 0.125 inches of bleed on each outer side.

Can I put text on the spine of a thin book?

Books with very few pages have a spine too thin for readable text. Around 79 pages is the usual minimum KDP suggests for spine text.

Does paper color change the spine width?

Yes. Cream paper is slightly thicker per page than white, so the same page count gives a wider spine.

Is this the same as KDP’s cover calculator?

It uses the same type of formula, but KDP’s template is the official source. Use this tool for planning and KDP’s template for final files.