running total for overtime

There are ways to do this. Depending on what your table looks like you could use an "expanding range" something like this:

In C2, filled or copied down the column:

=SUM(B$2:B2)

If your table setup is different, then you could post a screenshot? (shift-command-4, select area on screen, release, then insert image (placed on the Desktop by default) into a new post here using the 'mountain' icon at the bottom of the compose window).

SG

If you want a running total starting in E2 then you might try =SUM(D$2:D2) filled down.

SG