This post is my summary and my conclusions on the Path Length Limit in SharePoint Online and OneDrive.
How the path length is calculated Path Length is not the same as the URL length. It is the relative Url.
/sites/site-url/documenlibrary/folder1/folder2/filename.fileextension Calculations rules Only the server relative url part is counted. The “https://[tenant].sharepoin.com” has no impact on that. It starts from the foward slash: “/sites” (or /teams). An encoded value such as a blankspace (%20) is treated as one character, not three.