Cover specifications look like a mess of per-store numbers, and they are, but they overlap enough that one file clears all of them. Build for the strictest and stop reading the tables.
The one file to make
| Property | Value |
|---|---|
| Dimensions | 1,600 × 2,560 pixels |
| Ratio | 1:1.6 (height = width × 1.6) |
| Format | JPEG, quality 85–90 — or PNG if the art demands it |
| Colour | RGB, sRGB profile |
| File size | Under 5MB comfortably; stores allow more |
| Border | None. A drawn border looks like a mistake at thumbnail size |
That ratio is the tall paperback shape ebook stores standardised on. It is not A4 (1:1.41) and not the 2:3 of a photo print, so a cover designed on an A4 canvas will be letterboxed or cropped by whoever displays it — and you will not control which.
Where each store's minimum sits
| Store | Asks for | 1600×2560 clears it? |
|---|---|---|
| Amazon KDP | 1:1.6, 1,000px minimum on the long side, 2,560 ideal | Yes |
| Apple Books | At least 1,400px on the short side, JPEG or PNG | Yes |
| Kobo | 1,600 × 2,400 recommended | Yes |
| Google Play Books | 1,024px minimum on the long side | Yes |
| Draft2Digital and similar | Passes through to the above | Yes |
Specifications change; these are the shapes rather than a promise. But the direction of change has been consistently upward, so a file built to the largest of the current numbers has aged well for years.
The thumbnail test, which is the real one
Nobody discovers your book at 2,560 pixels. They see it about 150 pixels wide in a search grid, next to twenty others, on a phone, while scrolling.
So the test is simple and brutal: shrink the cover to 150 pixels wide and look at it. Then look at it after five seconds away from the screen.
- Is the title readable? If not, nothing else about the cover matters. This usually means fewer, larger words.
- Is it one idea? A detailed illustration becomes grey mush. A single strong shape survives.
- Does it read against both backgrounds? Stores show covers on white and on dark. A cover with a white background needs enough edge definition not to dissolve.
- Can you tell what kind of book it is? Genre signalling happens at thumbnail size, before anyone reads the title.
- Is your name legible? If you are not known, it can be small. If you are, it should not be.
Subtitles are the usual casualty. A long subtitle that reads beautifully at full size is a grey smear in the grid, and it is competing with the one element that has to survive.
The print cover is a different file
This trips people who assume the ebook cover can be reused. A paperback cover is a single spread — back cover, spine, front cover — at the physical size of the book, with bleed all round.
cover width = back + spine + front + bleed both sides
spine width = page count x paper thickness per sheet
300 pages on white stock:
300 x 0.0023in = ~0.69in spineTwo consequences follow. The cover cannot be finished until the interior page count is final, because adding four pages shifts the spine and everything positioned relative to it. And the file needs bleed and print resolution, which is a separate checklist.
Every print-on-demand service publishes a template generator: give it trim size, page count and paper, get back a PDF with the exact canvas and the safe zones marked. Use it rather than doing the arithmetic — what KDP asks for covers that end.
Inside the file, and the other places a cover appears
The cover has more than one job, and the same artwork rarely serves all of them without adjustment.
| Where | What it needs |
|---|---|
| The store listing | The 1,600 × 2,560 file |
| Inside the EPUB | The same image, set as the file's native cover |
| First page of a PDF | The artwork at the page's proportions, not the store's |
| A social post or ad | Often square or landscape — a crop that still works |
| Your own site | A smaller version, often with a shadow to read as an object |
The third row is the one that surprises people. A 1:1.6 cover dropped onto an A4 page leaves bands top and bottom, because the page is a different shape. If the PDF has a cover, it wants art proportioned for that page.
In bukpress, front and back cover artwork is part of the design rather than something you bolt on: the image you upload becomes the EPUB's native cover — the one the reading app shows in the library — and the covers of the PDF.
If you are designing it yourself
- Start at 1,600 × 2,560 rather than scaling up later. Enlarged type shows it.
- Pick one typeface for the title and set it enormous. Amateur covers are almost always timid.
- Use two colours and one image. Restraint reads as confidence at any size.
- Look at the top twenty books in your category and notice what they have in common — that is the genre's visual grammar, and ignoring it costs you readers who were scanning for it.
- Keep everything important away from the edges; store overlays and crops eat corners.
- Do the thumbnail test before you fall in love with anything.
And the honest note: a cover is the one part of self-publishing where paying someone reliably beats doing it yourself. It is the first thing a reader sees and the only part of the book they judge before deciding whether to read a word.