ISBN Example Generator

Generates an ISBN-13-shaped example number — 978-prefixed, correctly hyphenated, and with the check digit worked out rather than guessed, so it passes the validation a book-catalogue import performs. It is not a real, assigned ISBN and must never be printed on anything sold or catalogued.

Your result will appear here.

What this generator does

Produces an ISBN-shaped identifier for filling library and bookshop test data. ISBNs are issued by national agencies against real published works, so this generates the format rather than a genuine identifier — but it generates the format completely, check digit included, because a book-catalogue import that rejects every row of your test data has not tested anything.

How to use this tool

Press generate for an example ISBN.
Generate again for another one.
Paste it straight into a catalogue import — the check digit will pass.

Worked examples

Format: 978-0-123-45678-5 — thirteen digits, hyphenated into prefix, registration group, registrant, publication and check digit
What the last digit is for: Change any one digit of a generated number and the check will fail, which is the property that makes it useful as a fixture for the failure path as well as the success path.

Common use cases

Mock book-catalogue test data
UI/UX mockups needing a book identifier
Teaching ISBN formatting

How this generator works

The registration group, registrant and publication elements are drawn at random, and the thirteenth digit is then computed from the twelve before it by the alternating one-and-three weighting an ISBN-13 uses. That last digit exists so a scanner or an import routine can reject a mistyped number, which is precisely why test data needs it to be right.

Limitations and good to know

Not a real ISBN and will not match a catalogue record. Do not print a generated value on anything that will be sold or catalogued.
A correct check digit is not a registration. The twelve digits before it are drawn at random and could coincide with a real book's, which is a reason to keep these in test data rather than a reason to make them invalid.
The hyphenation follows the shape of an ISBN rather than the real registration-group and registrant boundaries, which vary by agency and by publisher.
It has no idea what a book is. Nothing here is checked against any bibliographic record.

A formatting example only, never a real, assigned ISBN for any published book. The check digit is correct so the number passes validation in test data; that also means it cannot be told apart from a real ISBN by inspection, so it must never appear on anything sold, catalogued or published.