Future Value of a daily savings account

[Beanis]

Hi All

I want to work out the future value of a daily savings plan in 1, 5, 10, 15, and 20 years.

I have tried the =FV function but the trouble is this:

It is based on the 10c saving challenge where you multiply the day of the year by 10c and that is what you put away that day. I have a savings account that allows me to do this pretty easily through the app.

=FV doesn't really work because it bases itself on the same amount for the period of investment. So the variables are this:

Day 1 - 10c, day 2 - 20c and so on for 365 days then you start from 10c again

7% interest per annum

What will the Future Value be in 1, 5, 10, 15, and 20 years.

I know it is a combination of =FV(rate, nper, pmt, [pv], [type]) and =PMT * ((1+i)^n - (1+j)^n) / (i-j) but I don't know how to adjust it to a daily increase of an amount and not a percentage.

Any help would be appreciated.

[#2]

@Beanis 

Since you end your request with the statement "Any help would be appreciated" I'm going to take you at your word and not try to actually solve it (although I'll be interested in the solution)...

If I were in your place, I'd look at one of the cash flow functions. IRR and XIRR in particular seem suited. I use the latter in calculations involving an irregular series of returns for some investment strategies where there are cash transactions both in and out to consider, varying amounts.

It's not a simple or single formula that it relies on, but a series of transactions, and given your situation, you may need (absent some formula based on calculus perhaps) to just set forth a daily "deposit" next to a series of dates....

OK, as I said, I'll be interested and now that I've responded I'll be able to see what other Excel folks come up with.

Have fun!