One way to read your question is how to do it mathematically - the quick
answer for that is
degrees + (minutes / 60) + (seconds / 3600)
In terms of how to work with DMS in Excel, another thread that includes
link John mentioned is at
'Format to Degrees, Minutes, Seconds - MrExcel Message Board'
(
http://www.mrexcel.com/forum/showthread.php?t=68869)
It probably makes a difference if you are dealing with longitude and
latitude or if you are working in the engineering realm where degrees
can be from 0 to 359...