A free ISBN is not a rights grab. It is an identifier. The real question is whether you care about publisher-of-record control, portability, and how each format will be distributed.
Buy your own ISBN when your publishing imprint is part of the business. Otherwise, a free ISBN can be a sensible way to publish professionally without spending hundreds before launch.
| Question | Free ISBN | Author-owned ISBN |
|---|---|---|
| Cash cost | $0 | $125 for one in the US, lower per ISBN in bulk |
| Publisher of record | Usually the platform or partner imprint | Your imprint |
| Copyright ownership | Still yours | Still yours |
| Best use | First books, test launches, cost-conscious authors | Imprint-led publishing, wholesalers, multi-platform control |
Use one ISBN for the paperback edition. If the trim size changes materially, treat it as a new format and assign a new ISBN.
Kindle can use Amazon's ASIN, but wide eBook distribution often benefits from an ISBN. Do not reuse the paperback ISBN for the eBook.
Hardcover is coming soon on Books.by. When you publish a hardcover edition, it needs a separate ISBN even when the text is identical to the paperback.
Small typo fixes do not need a new ISBN. Major revisions, new subtitles, substantially changed content, or a new format usually do.
Books.by can support ISBN assignment for eligible books published on Books.by, so authors are not forced into a Bowker purchase before they know the book will sell.
Not all platform identifiers are equal. Amazon's ASIN is not an ISBN and only works inside Amazon's catalog.
Title, subtitle, contributor names, imprint, format, and publication date should be settled before assignment.