A print book cover is a single flat file that wraps around the book: back cover, spine and front cover. Getting the dimensions right is what separates a cover that prints cleanly from one that is rejected or arrives with text cut off. These are the key terms.
Trim size
Trim size is the finished size of your book after it is printed and cut. It affects the width and height of the cover, so choose it before the cover is designed. Different platforms offer different sizes, so check what your chosen printer supports.
Page count and paper
The thickness of your book depends on how many pages it has and what paper it is printed on. That thickness becomes your spine width. If your page count changes after the cover is finished, the spine will usually need adjusting.
Spine width
Do not guess the spine width. Printers publish templates or calculators that give the exact figure for your page count, paper and binding. Text on the spine is usually only added when the spine is wide enough to carry it legibly.
Bleed
Bleed is extra artwork that extends beyond the trim edge so that no white edge appears if the cut is slightly off. The amount required depends on the printer, so use the figure in their template rather than a general rule.
Safe area
Keep important text and elements inside the safe area, away from the trim edge and the spine fold. Anything outside it risks being cut off or lost in the binding.
Barcode space
If your ISBN barcode goes on the back cover, leave a clear area for it. Some platforms add the barcode automatically, so check their rules.
Why the printer’s template matters
Every printer has slightly different specifications. Starting from their template for your exact format means your file is built correctly from the start. If you use Lulu, use the cover template for your chosen size, binding and page count.
The front cover still has to sell
Technical correctness is only half the job. Most readers first see your cover as a small thumbnail, so the title must be legible at small sizes and the design should signal the genre at a glance.
Need help?
Our book cover design service covers the front cover, the full print wrap and ebook versions, built to your printer’s specifications. Request a quote to get started.
