well yay thanks for the answer but i really need the formula lol I tried to derive it on my own but it was a little bit rough lol
i need the formula it wasn't in my book and I don't know what the name of the formula would be so i can't really google it...
The formula you want can be found here:
http://www.moneychimp.com/articles/finworks/fmbasinv.htm
In that formula, annual investments and interest payment for Y years is assumed. You let Y be the number of months, c be the monthly contribution, and r be the monthly increase factor, and use the same formula.