Converting time into cumulative minutes

Hi everyone,

I work for an FMCG company and I am trying to put together a daily report that tells everyone how far ahead or behind plan the lines are. (We have 25 lines)
I have a planned finish time in DD:MM:YYYY HH:MM and I have a current time in the same format.
What I am looking for is the number of minutes between these two times so that I can say Line 1 has 100 minutes until the plan says production should be finished.

The minute format needs to be a number so that I can use this to work out qty of shippers left.

So say it another way,
I can work out how many minutes left to finish the production given the quantity of shippers left to make and the nominal speed. e.g 100 minutes to finish production
I can work out how many minutes until the production was planned to finish if the deadline has not past.

I can't work out how to get the time after the deadline has past (e.g. -100 minutes)
or
to get the total minutes between planned finished and current time over multiple days.(e.g. 15th - 17th)
or
have a format that i can use to compute the ahead behind time.

I need these because I am saying;
Given that it will take 960mins to finish production given the planned quantity.
And there is 1020 minutes until the plan says we should be finished then

1020-960=60

This means we are 60 minutes ahead of plan.

Hope your collective wisdom can help me solve this issue.

I am just finishing a 12 hour night shift and wont be back until Thursday DS Australian time, so if I don't reply promptly I am not being rude, I am just not here.

Thanks to all.

Kieran

*1440_______________

Thanks, but I have figured it out. No response necessary. And no *1440 would not be an appropriate answer.