I need an Excel formula to add time?

Question

I have 3 cells. In cell 1, I have a time (8:00am). In Cell 2, I have an allotted amount of time for a speaker (15 minutes). In Cell 3, I want to put in a formula that will add the 15 minutes to my start time plus add a 5 minute buffer. What would that formula be?

Example:

Cell 1: 8:00

Cell 2: 0:15

Cell 3: 8:20

Answer 1

You're just missing the quotes:

= A1 + B1 + "0:05"

or

=SUM (A1, B1, "0:05")

Answer 2

First make sure your cells are formatted for time so it knows how to add it.

=sum(cell1-cell2)+5

Edit: use this is first don't work

=sum(cell1-cell2)+00:05:00