What Size Should an EPUB Cover Be?

There is no single pixel size built into the EPUB standard. A clean portrait cover with enough resolution for modern displays—and the right requirements for your store—is what matters.

Useful cover dimensions

Ratio matters as much as pixels

Changing a cover to a different ratio can crop titles, faces, borders, or publisher marks. Use Fit when every part of the artwork must remain visible. Use Crop to fill when edge-to-edge output matters and the subject has safe space around it.

JPEG or PNG?

JPEG usually creates a smaller file for photographs, painted covers, and textured artwork. PNG is useful for typography, flat-color illustration, or transparency, but can be substantially larger. WebP can be efficient, but JPEG and PNG remain the safer compatibility choices for broad reader support.

Do not upscale a small source unnecessarily

Increasing pixel dimensions does not recreate missing detail. Start with the largest clean source available. If the cover already looks soft or blocky, obtain the original export from the designer rather than repeatedly resizing a compressed copy.

Check the publishing destination

Retailer rules and recommendations can change independently of the EPUB specification. Confirm the current cover requirements for the store or distribution service you plan to use before final submission.