What formula could I use to calculate total minutes then populate it
in a column for a value in column like 11:40pm -- 12:20am

the sheet may look

A B (total minutes)
11:40pm -- 12:20am {auto cal and population}

I can re-arrange data to make it easier for Excel to look like this
(using 24hour schema)

A B C (total
minutes)
R1 11:40 12:20 {auto cal and population}

The calculation formula or expression in C1 would have to be something
like ((The first element of B1, that is, 12) - (the first element of
A1, that is, 11);
then, * 60) - (the second element of A1 - the second element of B1,
that is, 20)
= 40

I'm not Excel guru, can you parse/extract partial data set from a cell
like above?

TIA.