How do universities deal with the length of assignment submissions (e.g. word count) in pdf? My university requires all written work (essays, reports and dissertations) to be submitted electronically in Microsoft Word format. At my previous university, PDF was also acceptable (in fact, recommended).

In the UK, where I study, assignment length is determined by the number of words (not pages, as is usual in some countries).

As a LibreOffice user, submitting in Word format regularly results in formatting issues for which I can lose marks. The university has sympathised with this, as well as my ultimate preference of being able to use LaTeX, but insist it is not possible to accept PDF files because they can't easily do a word count.

Looking at other UK universities, it seems that a majority accept PDF submissions either exclusively or in addition to other formats. How do they deal with the issue of assignment length?
My only direct experience with this kind of academic word limit has been with my Master's and PhD dissertations. In both cases the official submission was in hard copy. Under those circumstances, I find it vanishingly unlikely that anyone did a word count -- I suspect that at my university, the word-limit rule would only be invoked if someone submits something that's blatantly too long (e.g. a 500-page MSc thesis).

I would guess that other universities deal with the issue of PDF word counts either by not caring much (as in the case of my dissertations), or simply by counting the number of words in the PDF: despite your university's insistence that this is impossible, there are dozens of free tools, both web-based and downloadable, which can accomplish this task. Even without those, Adobe Reader has a "save as text" function which produces an easily word-countable plain text file.

Another possibility is that those universities set the limits in terms of pages, not words.