How to convert CRLF and LF line endings
Operating systems mark the end of a line differently. Windows writes CRLF (carriage return plus line feed), while Linux and modern macOS write a single LF. Mixing them makes Git report a whole file as modified, makes Notepad show everything on one line, and can break config files and CSV imports. This tool converts between all three forms.
Line endings are invisible on screen, so a preview alone never tells you what changed. That is why the counts of CRLF, lone LF and lone CR are shown side by side, before and after. Lone CR breaks from classic Mac OS are converted by default; uncheck the option and they are left alone, with the result stating how many were skipped.
One thing worth knowing: a browser silently rewrites CRLF to LF in text typed or pasted into a text box. That is why the before column shows zero CRLF for pasted text. To see the original endings, load the file with the file picker above. You can copy the result or save it as a file; the clipboard may re-translate line endings on the way out, so save the file when the exact bytes matter.
Frequently asked questions
The browser normalizes CRLF to LF for anything typed or pasted into a text box. Load the original file with the file picker instead and the CRLF breaks are counted exactly as they are stored.
Use LF for Git repositories and anything headed to a Linux server. Use CRLF for files opened in Windows Notepad or for CSV files destined for Excel. Lone CR is effectively obsolete, so converting it away is the safe choice.