What size should a Kindle ebook cover be?

Amazon currently lists 2,560 pixels high by 1,600 pixels wide as the ideal size.

Should an ebook cover use RGB or CMYK?

Use RGB for the ebook cover file.

Why test the thumbnail?

Storefront results show the cover much smaller than the production file, so title shape and contrast must survive reduction.

Ebook cover size: pixels, ratio, file type, and thumbnail checks

What to check

1. Design at production size, but judge the cover repeatedly at retailer-thumbnail size

Design at production size, but judge the cover repeatedly at retailer-thumbnail size.

2. Keep the title as live type until export so spelling, line breaks, and hierarchy can be corrected

Keep the title as live type until export so spelling, line breaks, and hierarchy can be corrected.

3. Very light covers can disappear against a white storefront; Amazon suggests a narrow medium-gray boundary where needed

Very light covers can disappear against a white storefront; Amazon suggests a narrow medium-gray boundary where needed.

Use the final production inputs

Calculate from the final formatted page count, not the manuscript estimate. Select the exact trim, binding, interior type, and paper stock before creating the cover sheet. If any of those values change, regenerate the dimensions and compare the exported PDF against the printer's current template.

Artwork, type, spine, and back-cover copy remain editable when the print setup changes.

Sources: Amazon KDP ebook cover requirements. Recheck the current printer template before export.