time minus duration

**w1lls** · 07-21-2011, 10:34 PM

i´m trying to calculate a journey departure time from its duration and arrival time.
all very simple.. a=c-b

i think my problem is not recognising "b" (hh:mm:ss) as a duration but as an am/pm time and the sum is out of range..
how can i define the difference

thanks in advance :-)

**Paul** · 07-22-2011, 12:13 AM

Hi W1lls, welcome to the forum.

There are a number of examples of working with times here: http://www.cpearson.com/excel/datearith.htm#AddingTimes

Depending on how your cells are formatted, and whether or not they contain time values or text representations of such, can greatly impact your formulas. Perhaps post a sample workbook where you're seeing the issue. Delete any unnecessary sheets/data that don't pertain to this issue, along with any confidential names, etc.