LibreOffice Calc: How to get total for HH:MM:SS cells

I'd like to take a group of cells in the HH:MM:SS format, and add them up. I don't want to have the value wrap on the 24 hour clock. I just want an absolute total of the values. (The sum function seems to wrap by default).

So if I have:

20:00:00
20:00:00
00:10:00
00:00:10
00:00:10

I want to end up with:

40:10:20

A contrived example, but it gets across what I'm looking for.

Solution 1:

It's a matter of formatting the cells. You will have to apply the format code [HH]:MM:SS. It's already predefined:

(Screenshot from LibreOffice 3.4.3)

Solution 2:

Very often the time value is presented as a string ie. appears as '01:00:00 when formatted as time.

There are two solutions to this:

1. To delete the single quote. This is extremely tedious if there are more values

2. To create another cell which uses a formula to convert to timevalue. If eg A1 contains '01:00:00 then create another cell with =TIMEVALUE(A1), the formula can be dragged along to easily convert multiple values

Solution 3:

Another solution that I have used is to enter 01:00 AM as 25:00 it still displays as 01:00 but the math is then performed correctly.