Free tool · runs in your browser
Paste a column of ISBNs — straight out of a spreadsheet is fine. Each one is validated, converted between ISBN-10 and ISBN-13, hyphenated the way the ISBN Agency says it should be, and identified by registration group.
| Input | Valid | ISBN-13, hyphenated | ISBN-10 | Registration group |
|---|
Why hyphenation needs a lookup.
978-0-306-40615-7 and 978-0-3064-0615-7 contain the same digits.
Only the ISBN Agency's published ranges say where the publisher's prefix ends, which is why
most formatters either get it wrong or put the hyphens in fixed positions.
This page carries the agency's own range table, exported Thu, 1 Oct 2026 17:05:06 UTC. If a number falls in a range that has not been assigned to a publisher yet, it says so rather than guessing a split.
What it does not do. It never looks a book up. There is no catalogue here, so it cannot tell you the title, the author, the edition or what a copy is worth — only whether the number itself is well formed and who the registration group belongs to. Nothing is uploaded and nothing is stored; close the tab and it is gone.