Formula To Calculate Maximum Principal Debt

A previous poster explained what I also need; there were no responses,
so I thought I would try again.

Does anyone know of an Excel template--or a small stand-alone
program--that will calculate the interest/principal breakdown when
payments are varied in amount and frequency? Free or low-cost, please.
I need one that will work on my Mac/Office 2004. I will need to print
out periodic reports.

Here is the way the previous poster described it:
"Excel template: Loan Amortization for random/irregular payments,
figures days
between payment dates.
I have a loan with a variable beginning balance and irregular payments
with
annual large payment. (based on collections)
Would like to enter payment and date.
then Excel would figure days since last payment, interest amount,
principal
amount, Ending Principal balance.
And total interest paid, total pricipal paid
If I change the starting principal, excel would recalculate all
entries."

Thanks very much.

Very new in this board. If I post this question in the wrong forum please bear with me.
There is about 20 staffs in our department and I have made a spreadsheet with 12 tabs for each month of the year Jan-Dec. If each staff have 15 days annual leave each year and how can I make a formular that can automatically calculate the balance of annual leave and entered in the tabs of the following months. For example if staff A used 5 days in Jan how can the balance of 10days be entered in the tabs from Feb-Dec. If he use another 5 days in July the remain balance of 5 days be automatically entered in the tab from Aug to Dec. Likewise if staff A took 2 days sick leave in Jan, and 2 days in Mar how can this sick days be automatically sum up in the months after. I am doing this manually at the moment and it is very time consuming and also very easy to make mistake.
Thanks and sorry for this long questions

How can I calculate a 3% anual rent increase over 15 years (3% over the last year's rent)?

how can i find the coordinatres of the maximum point on a curve plotted in
excel????

hi guys,

i have a simple spreadsheet where i'm totalling a few values thru a formula. it's similar to this:

=D13*F13

i'm trying to create a funcion that says if d13 * f13 >= 300, i want the value to stay at 300 max and at the same time, if d13 * f13 < 300, i want the total to remain whatever it is.

i have been able to create both of these formulas successfully by themselves but i can't combine them. is this possible?

any help would be greatly appreciated!!