TEMPO
Info
Work out the spine, design the full KDP cover and create pixel-exact visuals (Kindle, social, banners) — templates, shapes, checks, 300 dpi PDF. Everything stays on your device.
This application runs sandboxed on your own device.
It cannot read your sign-in details, nor send in the background what you type into it: it cannot send anything over the network (at most it loads a fixed module from knpliv.com that runs on your device). Whatever it keeps, it keeps on your device and nowhere else, and you can always make it forget. Like everything published here, it was read over before going online.
About this tool
A spine that is too narrow shifts all the cover artwork, and Amazon only says so after you upload. Its width cannot be guessed: it depends on the page count and the paper, through a formula Amazon publishes but never applies for you.
The tool applies that formula, then works out the exact dimensions of the full cover file — back, spine, front and bleed — with a diagram drawn to scale, the interior page size and the printing cost per copy.
A second tab opens an editor built on that template. Import your images, crop and adjust them (brightness, contrast, saturation, black and white, blur…), set the title, author, blurb and spine text in fourteen embedded open-licence fonts, and add shapes and rules. Safe zones, folds, spine margins and the barcode area stay visible; checks flag an image under 300 dpi, text too close to the trim, or spine text under 79 pages.
Export produces a PDF at the exact size of the KDP cover file, bleed included, at 300 or 600 dpi, plus high-resolution PNG and JPEG files, the front alone for the ebook, and a blank template. The file is RGB, which KDP accepts and converts itself, and flattened into a single image, which settles the transparency question. For hardcovers Amazon publishes no formula: the spine and boards are estimates, to be replaced with the values from your KDP template.
The paperback figures were taken from Amazon’s help pages on 6 September 2026, each one read and then reopened by a second researcher whose job was to contradict it. Where two of Amazon’s pages contradict each other — the colour coefficient, the threshold above which a spine may carry text — both versions are shown rather than settled.
Nothing is sent anywhere: calculations, images and projects stay in your browser. The editor needs a computer or a tablet; on a phone, the tool gives the calculation and the template.
Since October 2026 TEMPO is part of this tool: the same editor also designs pixel-exact visuals — 1600 × 2560 Kindle cover, square posts, story, banner, quote card, A4, poster or a custom size — with forty templates, nearly ninety shapes, emoji, text styles, gradients, a shelf-size thumbnail preview and a legibility check measured against the real background. Visuals export as PNG, JPEG, WebP or multi-page PDF, and “Fit to KDP” places a visual on the front of a calculated cover. A TEMPO project kept in your browser or saved as a .json file can be picked up here; the original is never erased.