Calculating ultimate value of monthly pension contributions

[deadlyduck]

Hi,

Could someone confirm for me the correct mathematical formula which will calculate the ultimate value of 29 years 3 months worth of monthly pension contributions.
I'm guessing I need to use the 'future value formula' but (as far as I can make out) this formula requires you to use fixed contributions and a fixed interest rate over the entire period- a fairly significant restriction when it comes to pension contributions! If either of these variables were to alter (eg if I increase the monthly contributions starting in year X) do I basically have to do a series of FV calculations with the different interest rates or contributions to get the ultimate value of the fund?

Thanks for any help received!

Deadlyduck

{UPDATE 20-05-2005}

I have prepared an Excel file which [I think] calculates the future value of a pension fund for a period extending up to 40 years. It has the following features:

• assumes monthly contributions (not single premium annual type) and compounds on this basis;
• allows you to specify the start/ end date of monthly contributions;
• it allows for fixed (or no) increases in contributions at the anniversary date each year (at a future date, I'll modify the file to allow for variable contributions at each anniversary date instead of a fixed amount for all anniversary dates);
• allows you to vary % management charges, allocation rates, anticipated growth rates;
• the future value of the fund is computed at the end of each calendar year.

If anyone wishes to get a copy of the file, email me. In particular I'd greatly appreciate feedback re any logic errors in the file (I'm not sure but I think it seems reasonably correct ) or suggestions for improvements. The file size is approx 45 kb