One duration in A1, the other in A2:

=A1+A2

Format Custom as [s] for seconds, [m]:ss for mintues and seconds and
[h]:mm:ss for hours, minutes and seconds

--
Kind regards,

Niek Otten
Microsoft MVP - Excel

"Foghat" wrote in message
...
I want to be able to calculate time durations then add them all together

i.e hh:mm:ss 00:04:23 is 263 seconds and 00:05:35 is 335 seconds,
the
sum of these is 598 seconds or 00:09:58

Can anyone help as I dont even know where to begin

Many thanks