Clean and validate ASINs and ISBNs
Paste text copied from a page, an email or a spreadsheet and get back only the book identifiers it contains: 10-character ASINs, and 10- and 13-digit ISBNs whose check digit actually validates. Invalid codes are flagged rather than silently dropped, so you can see what was wrong with them.
Nothing is uploaded and nothing is saved. These tools read what you paste and do the work in your own browser. No data is sent to this server, stored in a cookie, or kept after you close the tab.
What is recognised
What is an ASIN?
A ten-character alphanumeric identifier used by Amazon — for example B08N5WRWNW. ASINs have no check digit, so they are extracted but not arithmetically validated.
How are ISBN-10 and ISBN-13 checked?
Both carry a check digit, and the tool computes it exactly: the ISBN-10 weighted sum modulo 11, and the ISBN-13 alternating 1-and-3 weighting modulo 10. A code whose check digit does not match is flagged as invalid rather than dropped.
Why are some ten-digit codes shown as ISBN-10 and others as ASIN?
A ten-digit all-numeric code is treated as an ISBN-10 (and validated). A code with letters in it can only be an ASIN.