I would assume that it is not unlimited, but I haven’t actually set a standard for myself for this piece like I have for the Title and Description. I realized today there absolutely a limit and the number is “70” characters. This includes “www“, “the domain name“, possibly a “category“, and then the page URL with the file extension such as “.html”.
On a page I had lengthy URL, but it got worse when the category and domain name was included. Here is an example of what I had.
www.domain.com/services/all-the-services-we-perform-in-one-super-long-line.html
Google has this url indexed as….
www.domain.com/services/all-the-services-we-perform-in-one-super-lo…
If I wanted the word “line” to be important it was being cut off. When considering your page url or slug make sure to include the full path.
I hope this helps someone else out there…