On Mon, 10 Aug 2009 21:06:41 GMT, Lars-Åke Aspelin
wrote:

On Mon, 10 Aug 2009 21:03:43 GMT, Lars-Åke Aspelin
wrote:

On Mon, 10 Aug 2009 13:34:01 -0700, israel
wrote:

Hi I have a column "A1" to "A300" with time data (06:19:21), how can I
subtract a half hour? The seconds should not be relevant in the final column.

Thank you

Try the following formula:

=FLOOR(G17-1/48,1/1440)

Hope this helps / Lars-Åke

=FLOOR(A1-1/48,1/1440)

in cell B1

Copy down to cell B300

Lars-Åke


In order to be able to handle times before 00:30 you have to revise
the formula a bit, like this:

=FLOOR(A1+1-1/48,1/1440)

But I suggest you go for the type of formula suggested in another
proposal based on the TIME function that is more easy to understand.

Lars-Åke