LibreOffice SUM period of time in the format HH: MM: SS

Question

I want to get the sum of several cells containing a time period in the format HH: MM: SS. In LibreOffice Calc 4.0.3.3, I copied time periods in the G14: G21 range and formatted the cells as Time HH: MM: SS. I also formatted cell G22 and inserted the following SUM function into it:

=SUM(G14:G21) 

Instead of the expected result, the function returns me this solution 00:00:00. Could you explain to me where I am wrong?

Answer 1

Your format is incorrect. HH wraps up every 24 hours. Try using [HH] instead of HH, then you get the total number of hours.

Answer 2

The problem was how the data was inserted. Even if the cells were formatted as Date, having analyzed them in more detail, I found that the values ​​are preceded by an "apostrophe". Thus, LibreOffice treats them as a text string, not a period of time. Removing the apostrophe solved the problem.