A printed book cover size is not defined by the dimensions of one page alone. For a flat paperback cover, add the back cover, spine width and front cover, plus the bleed required by the printer. An error of a few millimetres can displace titles or leave the spine off centre.
For a flat paperback cover, total width before bleed = 2 × closed book width + spine width. Height = closed book height. Then add the printer’s specified bleed.
Front cover, back cover and spine
A paperback cover is normally prepared as one continuous piece containing three areas. A hardback has a different construction involving boards, turn-ins and gaps, and therefore requires its own template.
Common book sizes
A5 measures 148 × 210 mm, but books are also produced at 150 × 210 mm, 170 × 240 mm and many other sizes. There is no single compulsory format for a novel or non-fiction book.
How to calculate the cover width
If the closed book is 150 mm wide and the confirmed spine measures 12 mm, the flat paperback cover is 150 + 12 + 150 = 312 mm before bleed.
Examples of flat cover dimensions
For a paperback cover without flaps, calculate the back-cover width, add the confirmed spine and then the front-cover width. If the printer requires 3 mm external bleed on every side, add 6 mm to the total width and 6 mm to the height. These are mathematical examples, not final production templates.
| Closed book | Example spine | Cover without bleed | File with 3 mm external bleed |
|---|---|---|---|
| 148 × 210 mm (A5) | 12 mm | 308 × 210 mm | 314 × 216 mm |
| 150 × 210 mm | 12 mm | 312 × 210 mm | 318 × 216 mm |
| 170 × 240 mm | 15 mm | 355 × 240 mm | 361 × 246 mm |
Important: the spine figures are assumptions used to explain the calculation. Do not derive them from grammage alone or copy them from another edition. You need the paper’s actual caliper, pagination and binding method. For hardbacks, covers with flaps or platforms with their own specifications, use the supplied template.
How to add bleed
If production requests 3 mm on each outside edge, a 312 × 210 mm cover becomes 318 × 216 mm after adding 6 mm to both total width and height. This is an example, not a universal instruction.
Why grammage alone cannot determine the spine
The number of sheets and the actual thickness of each sheet largely determine the book-block thickness. Two papers with the same grammage can have different bulk. The printer or paper supplier must confirm the final spine width.
Hardback cover dimensions
Rigid boards, gaps and covering-material turn-ins require different calculations from a paperback. Do not reuse a paperback file as though it were a hardback template.
Ebook cover versus print cover
An ebook cover is usually prepared as a digital image in the proportion required by the platform. It does not physically include a back cover and spine in the same way as a printed cover.
How to prepare the final artwork
- Confirm the closed format.
- Define the page count and paper.
- Obtain the final spine width.
- Request the template for the chosen binding.
- Design the front and back covers.
- Check all text and codes.
- Export the PDF and approve a proof.
Once the cover dimensions are ready, review the interior layout and ensure that its pagination matches the spine calculation. Any finishes or textured materials must also be agreed before final artwork.
Frequently asked questions
How large is an A5 front cover?
The front face can measure 148 × 210 mm, but the complete flat cover requires additional width.
Is bleed added to the spine?
Bleed follows the complete cover template; it is not added independently around each area.
Can I use the same file for a hardback?
Not without adapting it to the different construction.
Do you need to prepare a book for print? Tell us its format, page count, paper and binding.
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