Duplicate ISBN Finder
Find duplicate ISBNs in a list. Normalizes across ISBN-10 and ISBN-13 (so 0-306-40615-2 and 978-0-306-40615-7 are treated as the same book). 100% private.
🔒 100% private — deduplication runs locally in your browser.
Processed in your browser — your file is not sent to any server
How to Use
- 1
Paste your ISBN list
One ISBN per line, or comma/semicolon-separated. Mixed ISBN-10 and ISBN-13 are fine.
- 2
See duplicates grouped
Each duplicate group shows the canonical ISBN-13 and every raw entry with its line number.
- 3
Export the report
Download a CSV with one row per duplicate group, ready for spreadsheet cleanup.
Common Use Cases
- Clean up a book catalog for double listings
- Deduplicate ISBN exports from multiple sources
- Find repeated barcodes in library records
- Merge inventory lists without duplicating stock