Hi Peo,

MANY THANKS, it works

Kind regards
Mark Zak


"Peo Sjoblom" wrote in message
...
You can overcome that entering by -15:00 like

=-"15:00"

and format as time, meaning that using 1904 date system will
allow time displayed as negative while using windows default will not




--


Regards,

Peo Sjoblom


"Mark Zak" wrote in message
...
Appreciate your promt responce. I am still unable to enter negative
values,
for example negative hours:minutes (-00:15). I need to calculate time
differences
in relation to tide levels and need to input, say 13:00 (hours:minutes)
minus
negative value, say -00:15 (hours:minutes) to arrive at 12:45. Excel will
not accept negative hours:minutes data entry

Any thoughts ?
Thanking in anticipation
Mark Zak



"Peo Sjoblom" wrote in message
...
Toolsoptionscalculation and 1904 date system will allow you to do
calculations that return negative time. Note that all dates created
earlier will have 1462 days added to them
To convert back put 1462 in an empty cell, copy it, select the dates and
do editpaste special
and select subtract

--


Regards,

Peo Sjoblom


"Mark Zak" wrote in message
...
I need to enter negative time value (hour and minutes) in a table
calculating tides for secondary ports, for example 13:00 hours minus a
negative value such as 00:15 hours, i.e., 13:00 - (-00:15). Excell will
not allow negative time entry, is there any other way?

Appreciate your assistance
Regards
Mark Zak