Random ISBN Generator
Generate ISBN 10 and ISBN 13 numbers with a correct check digit for test catalogues.
Random ISBN Generator
ISBN-13, valid check digit
How many ISBNs
Format
How to use the ISBN generator
- Choose ISBN-13, the modern format, or the older ISBN-10.
- Generate one or many. Each carries a valid check digit.
- Copy or export the ISBNs, hyphenated for readability.
About Random Nr's ISBN Generator
The random ISBN generator creates ISBN 10 and ISBN 13 numbers with a correct check digit, for test catalogues and demo book data. Pick the format and generate as many as you need, and Random Nr works out the final check digit so each number is structurally valid, while matching no real published title.
What an ISBN-13 is made of
Since 2007 every new book uses a 13 digit ISBN, which is really a product barcode number with a book specific prefix. The parts break down like this.
| Part | Example | Meaning |
|---|---|---|
| Prefix | 978 or 979 | the book industry GS1 prefix |
| Registration group | 1 | language or region group |
| Registrant | 8473 | the publisher |
| Publication | 209 | the specific title and edition |
| Check digit | 4 | a mod 10 checksum |
The 978 prefix is the original book range, and 979 was added as it filled up. An ISBN-13 that starts 978 shares its check digit maths with retail barcodes, which is why a book scans at a till like any other product.
ISBN-10 and ISBN-13 check digits
An ISBN-13 ends in a mod 10 check digit: alternate digits are weighted 1 and 3, summed, and the check makes the total a multiple of 10. The older ISBN-10 uses a different mod 11 scheme where the check can be the letter X, standing for 10. The tool applies the correct calculation for each, so both validate, and a real ISBN-10 can be converted to 13 by prefixing 978 and recomputing the check, which is how older books gained 13 digit numbers.
Why these ISBNs are valid but not real books
Every ISBN here passes its check digit and matches the format, but the registrant and title parts are random, so none points at a real, catalogued book. They are for testing library systems, bookshop software and any field that validates an ISBN. For the retail barcode behind the ISBN-13, see the barcode generator.
More code and ID generators
Frequently asked questions
What is an ISBN
The International Standard Book Number that identifies a book edition. It comes in a thirteen digit and an older ten digit form, both ending in a check digit.
Are the check digits correct
Yes. ISBN-13 uses a mod 10 check and ISBN-10 uses a mod 11 check, which can be X. The tool calculates both correctly.
Are these real books
No. They are random valid looking ISBNs for testing, not tied to any published title.
Can I choose the format
Yes. Switch between ISBN-13 and ISBN-10 with a tap.
Is it free
Yes, free and with no sign up.
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For a retail barcode see the barcode number generator.