You should use Tools|Goal Seek
For an excellent visual introduction go to
http://mistupid.com/viewlets/excel/xlgoalseek.htm

You may also like to see http://www.homeandlearn.co.uk/ME/mes8p4.html


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Always provide your feedback so that others know whether the solution worked
or problem still persists ...


"Emma Hope" wrote:

Hi All,

I have a complicated situation, i have the scenario where we have a starting
value i.e. £100k and it grows at say 9% per annum, this could be calculated
daily/weekly/monthly/quarterly/biannually/annually etc. Say it is monthly, I
know i can use =FV(9%/12,12,0,-100,000).

Now the situation is complicated by the fact that there is going to be a
payment out (i.e. withdrawal) however this is not fixed it is a percentage of
the value at that point in time i.e. 12%, it is futher complicated by the
fact that this withdrawal is also periodic (i.e. daily/weekly etc) and at a
different timescale to the growth of the fund.

Finally, the FV is not actually the figure i want, it is the number of
periods. i.e. i am trying to work out how long the money will last if it
grows at X% and Y% is removed from the fund (where Y X obviously).

If i knew the period for each part, i could just work it out but it could be
anyone of the six periods for growth and for withdrawals i.e. 36 scenarios,
is there any other way than building a massive spreadsheet with each of these
36 scenarios and then working out when the figure gets to 0 and then finding
out that period?

Thanks for any help you can give.