How can I convert a value in the form of HH:MM:SS.111 to just seconds?

Originally Posted by alvin-chung

Try this formula and format it as [s].000 will yield the same result as your expectation.

Formula:

=TEXT(B2,"00\:00\:00\.000")-TEXT(A2,"00\:00\:00\.000")

EXCELLENT! This has done exactly what I needed!

Now I need to figure out how to mark this question as solved haha