I'm trying to add a sum of cells with the format HH:MM. If the sum exceeds 24h I get strange results like 3:55h
I tried [H]:MM:S
Which format should I choose? I'm using open-office calc.
For OpenOffice you should try [HH]:MM:SS
That will allow the number of hours beyond 24 to show (e.g. 12:00:00 + 13:00:00 = 25:00:00)