Book Cover Resizer (KDP) – everything it can do:

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Book Cover Resizer for KDP

Make your eBook or paperback cover exactly the size Amazon KDP and other stores ask for – spine, bleed and 300 DPI, ready to upload.

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Book Cover Resizer (KDP) at a glance

Price: Free
Account: Not needed
Watermark: None
Privacy: Files are processed inside your browser and are never uploaded.
Works on: Windows, Mac, Linux, Android and iPhone – in any modern browser
Install: Nothing to install

eBook covers for every storeKindle 1600 × 2560, Apple Books, Kobo, Google Play, Draft2Digital, IngramSpark and square audiobook covers for ACX – one picture, or all stores in one ZIP.

Paperback full cover, done rightChoose the trim size, paper and page count: the spine width, 0.125″ bleed and full cover size are worked out for you, with back cover text, spine text and barcode space.

Everything else a publisher needsCheck a cover before uploading, make 3D book mockups and social media posts, an ISBN barcode, and the interior page size and margins with a ready Word template.

How to use Book Cover Resizer (KDP)

Choose eBook cover, Paperback full cover or Any size at 300 DPI and select your picture.
Pick the store or the book size, paper and number of pages. The preview shows the trim line, spine, safe area and barcode space.
Download the cover – JPG for eBooks, a print-ready PDF for paperbacks – and upload it to KDP.

Why KDP rejects covers

Most rejected covers have one of four problems: the size is wrong (a paperback cover must include the back, the spine and the front plus 0.125″ bleed on every outside edge), the spine width does not match the page count and paper, the picture is below 300 DPI, or text sits too close to the edge and could be cut off. This tool fixes all four.

eBook cover sizes by store

Store	Size made by this tool	Notes
Amazon Kindle (KDP)	1600 × 2560 px	Height to width 1.6 : 1, JPG or TIFF, RGB, under 50 MB
Apple Books	1600 × 2400 px	At least 1400 px wide
Kobo Writing Life	1600 × 2400 px	JPG or PNG
Google Play Books	1600 × 2560 px	At least 640 × 1024 px
Draft2Digital	1600 × 2400 px	Tall rectangle
IngramSpark eBook	1600 × 2560 px	JPG only, RGB
Audiobook (ACX / Audible)	2400 × 2400 px	Square

Stores update their rules from time to time – check the store’s help page if a cover is rejected. If your picture is a different shape, choose to fill (crop a little), fit it with a blurred or plain background, or stretch it. Amazon suggests a thin grey border for white or very light covers so they do not disappear on a white page – the tool switches it on for you when your cover is light.

Paperback cover size: how it is worked out

Full cover width = bleed + back cover + spine + front cover + bleed. Height = bleed + trim height + bleed. KDP uses 0.125″ (3.2 mm) bleed. The spine width depends on the number of pages and the paper:

Black & white on white paper: 0.002252″ per page
Black & white on cream paper: 0.0025″ per page
Standard colour: 0.002252″ per page
Premium colour: 0.002347″ per page

For example, a 6 × 9 inch book with 300 pages on white paper has a spine of 0.676″ and a full cover of 12.926 × 9.25 inches – 3878 × 2775 pixels at 300 DPI. KDP allows text on the spine only when the book has more than 79 pages; the tool tells you when that applies.

Front cover only, or a full cover you already have

Have only the front? The tool builds the back and spine in a colour taken from your front cover, adds your blurb and the title and author on the spine, and keeps the barcode area (2 × 1.2 in, bottom right of the back) free. The bleed is filled by mirroring the edges of your picture, so nothing important is cut off. Already have a full wrap from a designer? Choose “A full cover” – it is resized to the exact size, and you are warned if its shape suggests a different page count.

Any picture at 300 DPI

Need interior pictures for a picture book, a print at 8 × 10 inches or an A4 poster? The third tab makes any number of pictures the exact print size at 300 DPI (or 150 or 600), with an option for KDP interior bleed (+0.125″ width, +0.25″ height). Save them as JPG, PNG or one PDF.

Hardcover and other printers

Hardcover covers wrap around the boards and use different measurements. Choose “Other size / other printer” and “Type the spine width myself”, then enter the sizes from the printer’s own cover calculator – for KDP hardcovers, from the KDP cover template.

More tools for publishers

✔ Check my cover – drop the file you plan to upload and see, line by line, whether the size, shape, file type, colour mode (RGB or CMYK), DPI and file size meet the store’s rules. For a paperback PDF it checks the exact size against your page count and paper and tells you if the spine or bleed is wrong. One click fixes it.
🎁 3D mockups & promo – a 3D paperback with a transparent background, your eBook on a tablet and phone, and ready posts for Instagram, stories, Facebook/X banners and Pinterest with your own headline. The publisher pack puts every store cover and every mockup in one ZIP.
🧰 ISBN barcode – an EAN-13 barcode from your ISBN (10-digit ISBNs are converted), checked for typing mistakes, with an optional 5-digit price add-on. Download it as SVG for crisp printing or as a 600 DPI PNG.
🧰 Page setup – the interior page size (with or without bleed) and KDP’s margins for your page count: 0.375″ inside for 24–150 pages, 0.5″ for 151–300, 0.625″ for 301–500, 0.75″ for 501–700 and 0.875″ for 701–828; outside at least 0.25″ (0.375″ with bleed). Download a Word template with mirror margins, a title page and chapter headings already set.

Frequently asked questions

What size should a KDP eBook cover be?

Amazon recommends 1600 × 2560 pixels (height 1.6 times the width), JPG or TIFF in RGB, under 50 MB. Choose “Amazon Kindle (KDP)” in the eBook tab and download.

How do I calculate my paperback spine width?

Choose your trim size, paper and number of pages in the Paperback tab. The spine is pages × paper thickness – for example 0.002252″ per page on white paper – and the full cover size is shown straight away.

Does KDP need 300 DPI?

Yes, for print covers and interior pictures KDP asks for at least 300 DPI. Every file made here is exactly the right size in pixels for 300 DPI and has 300 DPI written into it.

Why is my cover rejected for the wrong size?

Usually the spine width does not match your final page count, or the bleed is missing. Enter the exact page count of your final interior PDF and download a new cover.

Can I put text on the spine?

Yes, when the book has more than 79 pages – KDP does not allow spine text on thinner books. Type the title and author and the text is sized to fit safely inside the spine.

Is the barcode added?

KDP adds the barcode for you in the bottom right of the back cover. Keep “Keep the barcode space free” switched on so your text does not go there.

Can I make an audiobook cover?

Yes. Choose “Audiobook – ACX / Audible (square)” in the eBook tab for a 2400 × 2400 px square cover.

How do I check if my cover will be accepted?

Open “Check my cover”, choose your file and the store (or Paperback). Every rule is listed with ✓, ⚠ or ✗. Press “Fix it” to resize it correctly in one click.

Can I make a 3D mockup of my book?

Yes. In “3D mockups & promo” choose your front cover – you get a 3D paperback with a transparent background, the eBook on a tablet and phone, and social media posts with your own headline.

Do I need my own ISBN barcode for KDP?

No. KDP adds the barcode to paperbacks for you. Make one here only for other printers, such as IngramSpark, or if your designer needs it on the cover.

What margins does KDP need?

The inside margin grows with the page count (0.375″ up to 150 pages, up to 0.875″ for 701–828 pages) and the outside margin is at least 0.25″, or 0.375″ with bleed. The Page setup tool shows the numbers and gives you a Word template.

Is my cover uploaded anywhere?

No. Your pictures are resized and the PDF is made on your own phone or computer. Nothing is sent to a server, so unpublished covers stay private.

Can a small picture really become 300 DPI?

The file will be 300 DPI and the exact size, but enlarging cannot add detail that is not in the original. The tool tells you how much your picture is enlarged: up to about 1.5× usually prints well; more than that may look soft. For the sharpest result, start from the largest version of your design.