If you want it to show as 00:00 you could subtract 12 hours, and then format
as hh:mm

If, however, you format the cell as mm:ss you don't need to subtract the 12
hours.
--
David Biddulph

"Trevor" wrote in message
...
i have a start time in hrs and mins 12:00:00
how can this show up as 00:00