When subtracting one time from another, why do I get negative val.

[Guest]

cI'm trying to set up a worksheet (in excel) to tell me what time I would
need to start up certain items, in order to achieve an output for a specified
time. Ideally I would be able to type in the required output time & the
worksheet would show me what times other items would need starting. I know
how to subtract one time from another, but I can't figure out how to make it
understand that (eg) 40 minutes from 00:20 should show 23:40, any help? I'm
using excel 2002, but I'm at work so it would be easier for me to see any
answers if they could be e-mailed to (e-mail address removed)

 

[Bob Phillips]

Deano,

Use something like this to get your date

=MOD(G1-H1,1)

 

[SidBord]

There is so much to say about tiime arithmetic, that it's
beyond the scope of this message. One thing I've found is
that it's VERY important to have the result formatted
correctly. For example, if you are going over 24 hours,
then write the format usinig braces around the hours:
[h]:mm Also be careful that you subract properly (A - B
instead of B - A) to avoid getting negative time, which as
most of us know, there ain't such a thing. Formatting is
usually the key. Check out what Excel Help has to say
about time arithmetic, or get a good Excel reference book.