Files and uploading overview

File formats

Google accepts the following file formats:

We recommend that you provide your content both as an ePub file and as a PDF file if possible, as this will provide more viewing options for readers. However, only one format is necessary.

Even when the cover image is embedded within the ePub or PDF file, you may wish to submit the cover image in a separate file. Google will use this file when displaying the book cover as a thumbnail.

Content guidelines

Before you upload any files, please ensure your content meets our guidelines. If you plan to sell your books on Google Play, please also review our publisher content policies for books on Google Play.

Size limits

  • Each file (including cover image files) should be less than 2 GB in size.
  • The book should be at least four pages long.

Format-specific guidelines

  • The PDF file must consist of the complete book (or be one of a set of specially named multi-part files). Do not upload sample content (such as an excerpt); your Google Books settings control the amount that a user can preview.
  • The PDF file must not be password-protected, as this will prevent our system from processing the file.
  • For our system to automatically generate a table of contents, include bookmarks in the PDF file.
  • The ePub file must contain the front cover image.
  • The ePub file must consist of the complete book. Do not upload sample content (such as an excerpt); your Google Books settings control the amount that a user can preview.
  • The ePub file should be validated by EpubCheck.


Check the table below for example filenames, depending on how you plan to submit your files.

A single PDF file that includes the cover
  • Content and cover
    • [ISBN].pdf
A PDF file that does not contain covers; cover images provided in separate files *
  • Content, no cover (required)
    • [ISBN]_interior.pdf
  • Front cover (required)
    • [ISBN]_frontcover.jpg (file extension may differ)
  • Back cover (optional, but should be uploaded first if submitted)
    • [ISBN]_backcover.jpg (file extension may differ)

* Our system will not process an incomplete set of files. Read more.

A book split into multiple PDF files *
  • Cover and content
    • [ISBN]_1of3.pdf (numbering may differ)
    • [ISBN]_2of3.pdf (numbering may differ)
    • [ISBN]_3of3.pdf (numbering may differ)

* Our system will not process an incomplete set of files. Read more.

An ePub file
  • Content, including cover (required)
    • [ISBN].epub
  • Front cover (optional; used for marketing thumbnail)
    • [ISBN]_frontcover.jpg (file extension may differ)

Which identifier to use:

  • If you upload files for a single book from the book's "Content files" page: You don't need to include the identifier in the filename. Otherwise, the identifier is necessary for our system to associate the file with the correct book. Our system will use the filename extension to determine what kind of file you've uploaded.

  • If your books already have unique identifiers (such as an ISBN or a Google-assigned GGKEY): Replace [ISBN] in the example filenames above with the book's actual identifier. (For GGKEYs, you don't have to include the GGKEY: prefix.) If you have both a print and an electronic ISBN, we generally recommend naming your PDF files using the print ISBN, and naming the ePub files using the electronic ISBN. See more information about ISBNs.

  • If your books don't have unique identifiers: You can use your own filenames, replacing [ISBN] in the example filenames above with text of your choice. We recommend that you avoid using the underscore character ( _) except as noted in the examples (e.g., _interior or _frontcover).

Cover files

Cover files should be in JPEG, PDF, TIFF, or PNG format and have the appropriate filename extension.

How to upload files

There are two ways to upload files in the Partner Center:

  • Upload files for a single book (from the Content files page of the book's settings).

  • Upload files for as multiple books at the same time (from the Book Catalog, using the Add Content for Books function).

Multiple files for a single book

For the following cases, you should submit all the required files in order for our system to process your book:

  • a book split into multiple PDF files (e.g., ISBN_1of2.pdf and ISBN_2of2.pdf)
  • a PDF file without a cover accompanied by a separate cover image file (e.g., ISBN_interior.pdf and ISBN_frontcover.jpg)

If you are submitting a separate back cover image file (ISBN_backcover.jpg), we recommend that you upload it before you upload the content file (ISBN_interior.pdf).

If all the required files aren't submitted at the same time, they will be listed as "Pending" on the "Content files" page for the book and our system will not process the content or cover until all the expected files have been submitted. For example, ISBN_frontcover.pdf will remain in "Pending" status until ISBN_interior.pdf is uploaded.

Updates for these books are also processed differently.

How to update files

You can update a file in our system by uploading the new version. It will overwrite the old version in our system.

If you submit an updated file from the Book Catalog (rather than from the specific book's "Content files" page), the updated file should either use the same filename as the original file, or use the identifier as a prefix (such as in the examples above). Using a different filename or a filename that doesn't contain the identifier will generate a new book listing in your Book Catalog.

Books with multiple files:
  • Multi-part PDFs (e.g., ISBN_1of2.pdf and ISBN_2of2.pdf): You must re-submit all the files, even if not all of them are being updated.
  • A PDF file without the cover (e.g., ISBN_interior.pdf and ISBN_frontcover.jpg): You must re-submit the content (ISBN_interior.pdf) in order to trigger the processing of the most recent set of files.

File history

You can view a history of past submitted files by visiting your Book Catalog, clicking the book title, then going to the Content files page.

Our system will only use the most recent successfully processed file of each type (i.e., the most recent ePub file, the most recent PDF file, and the most recent cover file). At this time, there's no way to remove older records from a book's content files history.

Filenames listed in the history may differ from the filenames you used when submitting files. Our system will rename any files submitted from the "Content files" page to include the identifier in the filename. This won't interfere with the processing of your files.