Getting cover dimensions wrong wastes time and can silently hurt your book's presentation. Upload a cover that's too small and your thumbnail looks soft against professionally produced competitors. Upload at the wrong aspect ratio and the platform crops or letterboxes your design in ways you didn't intend. This guide consolidates the current requirements for every major ebook distribution platform into one reference so you can design once and upload everywhere without surprises.
The Universal Starting Point: Design at 1600 x 2560 Pixels
Before getting into platform-specific requirements, here is the practical answer for authors distributing to multiple stores: design your cover at 1600 pixels wide by 2560 pixels tall, saved as a JPEG or PNG at the highest quality setting your tool allows. This combination satisfies the minimum requirements of every major platform, maintains the standard 1:1.6 book cover aspect ratio, and produces a file size that falls within upload limits across the board. If you only remember one number from this guide, remember 1600 x 2560.
The reason this works universally is that the ebook industry has converged on the 1:1.6 (or very close to it) aspect ratio as the standard. Platforms that specify different pixel dimensions are almost always specifying different sizes at the same ratio, not fundamentally different shapes. An image designed at 1600 x 2560 can be scaled to any platform's preferred dimensions without changing the composition.
Amazon KDP Cover Requirements
Amazon Kindle Direct Publishing is the largest ebook market and sets specifications that most other platforms have implicitly aligned with. The current KDP requirements for ebook cover images are: minimum 1000 pixels on the shortest side, minimum 625 pixels on the longest side, recommended 1600 x 2560 pixels, maximum file size of 50 MB, and accepted formats of JPEG and TIFF.
KDP's ideal ratio is 1.6 (height divided by width), which is what the 1600 x 2560 recommendation represents. Covers that deviate significantly from this ratio — notably covers that are closer to square or nearly as wide as they are tall — will display with white padding bars in the Kindle storefront and on device home screens. This is immediately visible and looks unprofessional. There is no reason to use a non-standard ratio for a book cover intended for KDP distribution.
KDP also generates thumbnail versions of your cover for use in browse categories and recommendation widgets. These thumbnails are typically 100 to 160 pixels wide. At this size, covers with small text, busy backgrounds, or low contrast are essentially illegible. Design your cover so the title reads at 160px width — this is the most useful test for KDP thumbnail quality and is a practice that benefits your cover on every other platform as well.
Apple Books Cover Requirements
Apple Books requires a minimum cover size of 1400 x 1873 pixels with the same 1:1.6 aspect ratio, accepting JPEG and PNG formats at RGB color mode. The maximum file size is 4 GB, which is not a practical limit for cover images. Apple Books is particularly sensitive to cover quality in editorial featuring decisions — books selected for Apple's curated collections are often chosen partly based on cover quality, which makes meeting or exceeding the minimum requirements more important here than on purely algorithmic platforms.
If you distribute through Draft2Digital or Smashwords to Apple Books, those aggregators handle the format conversion and submit to Apple on your behalf. Your responsibility is to supply the aggregator with a cover that meets Apple's minimums, which the 1600 x 2560 universal file does comfortably.
Kobo Writing Life Cover Requirements
Kobo Writing Life, the self-publishing platform for Kobo's store and partner retailers, accepts cover images at a minimum of 800 x 1200 pixels and recommends 2400 x 3600 pixels for optimal display quality. The accepted formats are JPEG and PNG. The 1:1.5 ratio implied by Kobo's recommendations is very close to the standard 1:1.6 — a 1600 x 2560 cover will display without distortion on Kobo because the ratio difference is small enough that the platform scales without noticeable letterboxing.
Kobo has expanded its reach significantly through partnerships with independent bookshops in the UK, Canada, and Australia through its Kobo Plus and library programs. For authors targeting English-language markets outside the United States, Kobo is second only to Amazon in ebook market share in several regions, which makes quality Kobo presentation more commercially important than many Amazon-centric authors realize.
Barnes and Noble Press Cover Requirements
Barnes and Noble Press (formerly Nook Press) requires cover images at a minimum of 750 x 1000 pixels, accepts JPEG and PNG, and recommends the standard 1:1.6 ratio. The platform's thumbnail display is similar to KDP's in the sense that covers need to work at small sizes in category browse views. B&N's market share in ebooks has declined over the past decade and the platform represents a smaller percentage of most indie authors' revenue than it once did, but it remains relevant for authors with US audience and maintains a presence in physical Barnes and Noble retail stores for print editions.
Draft2Digital and IngramSpark: Aggregator Requirements
Draft2Digital, which distributes to Apple Books, Barnes and Noble, Kobo, Scribd, OverDrive (libraries), and several other retailers, applies a simple standard: minimum 1400 x 2100 pixels, JPEG or PNG, under 10 MB. The 1600 x 2560 file meets these requirements. Draft2Digital will handle formatting for individual retail partners from your single uploaded file.
IngramSpark, which is primarily used for print distribution but also handles ebook distribution, requires ebook covers at a minimum of 1600 x 2560 pixels and a maximum of 8 MB. The file needs to be in JPEG or PDF format. IngramSpark's ebook distribution reaches libraries and library systems at scale through OverDrive and similar platforms, which is a distribution channel Draft2Digital also covers but that Amazon KDP does not.
Smashwords (Now Part of Draft2Digital)
Smashwords merged with Draft2Digital in 2022 and the combined platform now uses Draft2Digital's requirements. If you have existing Smashwords guidance suggesting different specifications — particularly the older Smashwords Style Guide requirements — the current standard is Draft2Digital's: 1400 x 2100 pixels minimum, preferably 1600 x 2560 or larger.
Color Mode: RGB, Not CMYK
Every platform listed here requires RGB color mode. This is worth stating explicitly because authors who hire print designers sometimes receive covers in CMYK mode (the standard for print production) without realizing the difference. A CMYK file uploaded to a digital platform will either be rejected or will have its colors auto-converted in ways that can shift the palette noticeably — particularly deep reds, which shift toward orange in CMYK-to-RGB auto-conversion. If you use Photoshop, check that your document is set to RGB color (Image menu, Mode). Canva and Adobe Express output RGB by default.
Practical Checklist Before Upload
Before uploading your cover to any platform, run through this list: the file is at least 1600 x 2560 pixels; the aspect ratio is as close to 1:1.6 as your design allows; the file is saved as JPEG or PNG in RGB color mode; the title text is readable at 160 pixels wide; the file size is under 10 MB (most covers from design tools are well under 5 MB). If all five conditions are met, your cover will display correctly on every major ebook platform without any platform-specific adjustments. That is the goal: one file, every platform, no surprises.