Book Spine Calculator
Book spine width depends on cover thickness and book block thickness. We've prepared templates for the most common sizes, each with a preset spine width. Based on your book specifications, use our hardcover or perfect bound spine calculator to adjust the spine width on the template. Depending on the final construction of the book block, we may adjust the spine width as needed.
Hardcover
Perfect Bound
About the Spine Calculation
Elements of the Calculator
To get the right spine width for your hardcover or perfect bound book, you’ll need three things.
- the number of pages
- the thickness of the cover board
- the paper weight
It’s important to note that each book printer sources paper from different manufacturers, and with thousands of types of paper out there, even paper labeled with the same weight can have different thicknesses. Our calculator is tailored to the paper we use, and you can request a paper sample here to see what suits your preferences best.
Paper Thickness and Its Impact on Spine Width
In addition to these three components, the thickness of a hardcover book is also influenced by the case-bound cover—the paper that wraps around the board—and the endsheet, which connects the cover to the pages. The space between the stacked signatures also plays a small role. Once the book block is constructed, we will measure it again and make adjustments if needed.
Different paper weights (measured in GSM or lb) can significantly impact the spine width. Our calculator accounts for these differences, but here’s a handy table to show how various paper thicknesses and its actual thickness in mm.
For our calculator, we measure 100 pages with various paper weights, average the results, and determine the thickness of each page. This allows us to provide a reliable estimate of the spine width.
Interior Paper Weight vs Thickness
| Paper Weight (lb) | Thickness (mm/page) |
|---|---|
| 65lb Glass White | 0.058 |
| 70lb | 0.045 |
| 85lb | 0.05 |
| 105lb | 0.075 |
Hardcover Case vs Thickness
| Board,Wrap and Endsheet | Thickness (Front and Back Combine) |
|---|---|
| 2.5mm Board | 5.5 |
| 3.0mm Board | 6.5 |
| 3.5mm Board | 7.5 |
Perfect Bound Cover vs Thickness
| Perfect Bound Cover | Thickness (Front and Back Combine) |
|---|---|
| 12pt Cover | 0.45 |
| 13pt Cover | 0.57 |
| 14pt Cover | 0.69 |
About Applying Spine Width
Modify the Spine Width on Our Template
Once you've determined the spine width, visit our hardcover template page or perfect bound template page to download the appropriate template. If you don't find the exact size you need, you can either create one yourself or contact us for a custom template that perfectly fits your book.
When you open the template in a program like Adobe Illustrator, you'll notice the spine is preset to 26.5mm. Simply adjust the spine width to your calculated size, realign the other elements of the template, and save it. This will give you the correct template for your book.
About Common Spine Design Pitfalls
When you send over the file, we will run a pre-check. While it’s not our obligation, we do our best to point out any obvious potential issues in the production file. Here are a few common mistakes we’ve observed:
Spine Orientation
When designing the spine on a 2D screen, it’s important to ensure the orientation is correct. It can be hard to notice on screen, but if the orientation is wrong, the text will be upside down when the book is facing up.
Spine Misalignment
A safe spine design helps prevent misalignment issues. Precise elements like straight lines on the spine can shift if not correctly aligned, impacting adjacent pages. We remeasure the book block once complete to ensure a perfect fit. However, since not all printers are as precise, a conservative design reduces misalignment risk for a polished final look.
Bleed and Margin
Just like with the interior pages, it’s important to keep a 1/8" bleed and a 1/8" safe area away from the edge. Also, ensure the spine text and design are centered from top to bottom.
Spine Text Too Small
Book Spine Design is crucial because it helps your book stand out on the shelf. However, it's important to ensure the font size is appropriate and readble. And if you're using finishing techniques like foil, it's best to have lines that are at least 1mm thick to ensure the foil applies smoothly. To check the sizing, we recommend printing the cover at full scale using your home printer.
Other Book Types
For dust jacket spine width, you can use the same measurement as the hardcover. You can find the dust jacket template on our dedicated page. To calculate the spine width for a board book, visit the template page for more details. The calculation is simple: multiply the number of pages by the board thickness. At Ken the Book Printer, we use 1mm standard boards.