Find ISBNs in pasted text or a file
Paste text into the input area to detect ISBN-10 and ISBN-13 candidates. The extractor recognizes bare values and values separated with hyphens or spaces. You can also select Upload or drop a .txt, .csv, .json, or .log file on the input. Loading a file replaces the current input text.
Review and filter the extracted ISBNs
Use the controls below the input to change which matches remain visible.
- Unique only removes repeated normalized ISBN values, so separator differences count as the same identifier.
- Valid checksum only is enabled by default and removes invalid candidates from the displayed results. If you clear it, invalid candidates can appear with an
Invalid checksumstatus. - Normalize (strip hyphens/spaces) removes hyphens and spaces from the displayed ISBN while preserving an ISBN-10 trailing
X.
Use the results and output formats
The results table shows each displayed ISBN, its type, checksum status, source line, and nearby text context. The counter reports the number of displayed ISBNs. If filtering leaves no matches, the table is hidden.
With normalization off, the output uses hyphen groups generated by the script rather than preserving the separators from the source. Turn normalization on for separator-free output. Select Copy to copy the displayed list or Download to save it as a text file.
How to extract ISBNs
- Paste text into the input area, or select Upload and choose a supported file.
- Review the extracted ISBNs and their line and context details.
- Adjust Unique only, Valid checksum only, and Normalize (strip hyphens/spaces) as needed.
- Select Copy or Download to take the displayed list elsewhere.
Limitations and processing scope
Checksum validation confirms the ISBN format and checksum structure only. It does not confirm that an ISBN was assigned to a real book or retrieve titles, authors, publishers, or other metadata. ISBN parsing and file reading occur client-side, and the extractor code does not send the input text to a server. The page does not document a maximum input size, result limit, browser compatibility range, encoding behavior, or a user-facing error for unsupported files or file-reading failures.
Frequently Asked Questions (FAQs)
What's the difference between ISBN-10 and ISBN-13?
ISBN-10 has 10 characters, and its final check digit can be a numeral or X. ISBN-13 has 13 digits and uses a 978 or 979 prefix. The extractor validates each format with its corresponding checksum rule.
Does this tool check if an ISBN actually corresponds to a real book?
No. It validates the format and checksum only. It does not look up a book database or confirm that the identifier has been assigned to a real title.
What formats of ISBN does this tool recognize?
It recognizes ISBN-10 and ISBN-13 strings with hyphens, spaces, or no separators, including an ISBN-10 trailing X.
Why is this tool separate from the DOI Extractor?
An ISBN identifies a book edition, while a DOI identifies a digital object such as a scholarly article or dataset. They use different formats and checksum rules, so the tools handle them separately.