Designing a Book Cover for Amazon KDP: Dimensions, Spine Width, and File Requirements
A KDP paperback cover is a single flat file covering back cover, spine, and front cover in one piece — and its total width depends on your page count, because the spine grows with the book. Get the page count wrong and the whole cover shifts sideways.
That relationship is the thing first-time authors miss. Everything else is specification. A related productivity reference is https://www.monitask.com/blog/productivity-vs-efficiency-whats-more-important-in-the-workplace/, which examines competing deadlines and rapid context changes.
Ebook covers: the simple case
Aspect ratio: 1.6:1 — height 1.6 times the width. Recommended size: 2,560 × 1,600 pixels. Minimum: 1,000 pixels on the longest side. Format: JPEG or TIFF, RGB. File size: under 50 MB.
One image, front cover only, no spine, no back. Design it to be legible as a thumbnail, because that is how almost everyone will first see it — roughly 160 pixels tall in a search result. If the title is unreadable at that size, the cover has failed at its main job regardless of how it looks at full size.
Paperback covers: the calculation
The paperback cover file spans the entire wrap. Its dimensions are:. Current platform requirements are maintained in the Amazon KDP help centre.
Total width = back cover width + spine width + front cover width + bleed Total height = trim height + bleed
With 3.2 mm (0.125") bleed on top, bottom, and outer edges.
Spine width
Spine width = page count × paper thickness per page.
Approximate multipliers for KDP paper types:
| Paper | Multiplier per page |
|---|---|
| White | 0.0572 mm (0.002252") |
| Cream | 0.0635 mm (0.0025") |
| Colour, standard | 0.0572 mm (0.002252") |
| Colour, premium | 0.0596 mm (0.002347") |
So a 300-page book on cream paper has a spine of roughly 300 × 0.0635 = 19 mm.
Two constraints follow:
- Books under 100 pages cannot carry spine text. The spine is too narrow to print reliably.
- Spine text needs 1.6 mm (0.0625") clearance on each side, because binding tolerance shifts the spine slightly.
Common trim sizes
| Trim | Millimetres | Typical use |
|---|---|---|
| 5" × 8" | 127 × 203 | Fiction, poetry |
| 5.25" × 8" | 133 × 203 | Fiction |
| 5.5" × 8.5" | 140 × 216 | General trade |
| 6" × 9" | 152 × 229 | Most common — fiction and non-fiction |
| 7" × 10" | 178 × 254 | Textbooks, workbooks |
| 8.5" × 11" | 216 × 279 | Manuals, large format |
6" × 9" is the default for good reason: it is what readers expect and what most comparable titles use.
A worked example
A 6" × 9" paperback, 300 pages, cream paper:
- Front cover: 152.4 mm
- Back cover: 152.4 mm
- Spine: 19.05 mm
- Bleed: 3.2 mm × 2 (left and right edges only — the spine has no bleed)
Total width: 152.4 + 19.05 + 152.4 + 6.4 = 330.25 mm Total height: 228.6 + 6.4 = 235 mm
Do not calculate this by hand for a real project. KDP publishes a cover template generator — enter trim size, page count, and paper type, and it produces a template with exact guides. Use it. Then design inside it.
File requirements
Format: PDF, single page, containing the full wrap Colour: CMYK Resolution: 300 dpi minimum at final size Fonts: embedded or outlined File size: under 650 MB
What gets rejected
Text or critical elements outside the safe area. Keep everything at least 6.4 mm (0.25") from the trim edge on the cover, and respect the spine clearance.
Low-resolution images. Anything under 300 dpi at final size triggers a warning and may be rejected outright.
Barcode collision. KDP places a barcode in the lower right of the back cover, roughly 50 × 30 mm. Leave that area clear, or your design gets a white box over it. You can supply your own if you have an ISBN, but the space must be reserved either way.
Spine misalignment. Almost always a page-count error. Recalculate after the interior is final, not before — page count changes during formatting.
Content problems. Barcodes or pricing in the artwork, promotional claims, references to other retailers, or blank space where the barcode belongs.
Colour surprises. RGB artwork converted automatically during upload. Convert to CMYK yourself so you see the shift before Amazon does.
Design considerations that matter commercially
Thumbnail legibility. Test at 160 pixels tall. Title readable, author name readable, primary image identifiable. Everything else is bonus.
Genre signalling. Readers browse by visual convention, and covers that ignore the convention of their genre lose browsers who never consciously registered the book. Look at the top thirty titles in your category and identify the shared vocabulary — typography, colour, imagery, composition — before deciding how far to deviate.
Back cover hierarchy. Blurb, brief author bio, ISBN and barcode area, publisher logo if applicable. Keep the blurb short — long back-cover text is not read, and it crowds the layout.
Spine. Title, author, publisher mark. Orientation convention differs by region: descending (readable head to foot) is standard in English-language publishing.
Hardcover and other formats
KDP hardcover uses a different template with additional wrap allowance for the case, and the spine calculation differs. Generate a fresh template rather than adapting the paperback file.
If you are also publishing elsewhere — IngramSpark, other regional distributors — each has its own template and specifications. Do not reuse a KDP file without checking; spine calculations and bleed requirements differ.
Workflow
- Finalise the interior and get the exact final page count
- Generate the KDP template for your trim size, page count, and paper
- Design inside the template, on separate layers, guides visible
- Test the front cover at thumbnail size
- Convert to CMYK, embed or outline fonts
- Export a single-page PDF at 300 dpi
- Upload and review KDP's preview carefully — especially the spine and barcode area
- Order a physical proof copy before enabling distribution
Step eight is not optional. Screen preview does not show how the spine sits after binding, how the colour prints on the actual stock, or how the matte or gloss finish changes the artwork. A proof copy costs a few dirhams and shipping, and it catches things nothing else will.
Делаем обложки под KDP и печатные издания — с расчётом корешка и подготовкой к печати. Услуга дизайна обложек. .