Huseyin,
The formula you are looking for is...
-((P*(i/12)*(1+(i/12))^(n*12)))/(((1+(i/12))^(n*12))-1)
where
P = Principal amount
i = Annual interest rate
n= Period of loan in years

Example:
Principal $100,000
Interest 10%
Period - 30 years

-((100000*(0.1/12)*(1+(0.1/12))^(30*12)))/(((1+(0.1/12))^(30*12))-1) =
-877.571570088799

In Excel, -PMT(0.1/12,30*12,100000) = 877.571570088799

Identical to at least 12 places! If that isn't good enough for your
clients, you will never satisfy them.

I got this information off the web. Check out...
http://invest-faq.com/articles/analy...te-return.html

Hope this helps and good luck.
Gary Brown


wrote:
Thank you for replying to my post.
I am actually a business analyst defining amortization for developers
therefore I need to provide them the full mathematical formulas. I
cannot use any built in functions of any application. They need to
know
the exact formulas.

Let me know if you know what the PMT function involves. Thanks for
the
sample, it works nicely.