isbn converter - Robuta Search

https://www.isbn.org/ISBN_converter

https://isbnconverter.sampo.co.uk/

Convert multiple ISBN's using this free ISBN converter. Enter ISBN-10 or ISBN-13 to be converted.

https://www.loc.gov/programs/preassigned-control-number/isbn-converter/

This tool converts original ISBNs to hyphenated ISBNs