I have a log sheet where a nurse will enter the time in and time out. I have
a formula giving the total time in clinic. What is the best way to set up
formatting for entry?

I don't want the nurse to be required to type a colon, but I do need her to
do AM or PM.

My formula for figuring the time duration is:

=TEXT(IF(M2-L20,M2-L2,""),"h:mm")

Is this the best formula for ease of entry?

I would like her to type time in to be "130p" and time out "215p" and my
formula to display "00:45" I need am/pm so that it can figure time in
"1245a" and time out "115p"

I need help!!!

Cyrus