Here's the information of the repayment schedule I received from the bank:

Interest Rate P.A.: 3.25
Instalment Effective Date: 1 Jan 2007
Each Instalment Amount: 4,712.10
Final Instalment Date: 1 Jan 2017
Number of Outstanding Instalments: 121
Final Instalment: 4709.26
Schedule Outstanding Balance on 4 Dec 2006: 485,604.50


Below is the repayment schedule of the next 48 instalment:

Date Due: 1 Jan 2007
Inst. No.: 120
Interest: 1,315.17
Principal: 3,396.93
Outstanding Balance: 482,207.57


I'd like to know the algebraic formula --and the necessary steps -- used to calculate the fixed monthly payment and loan balance. My objective is to
work out a mortgage table just in case the interest rate varies.

I shall appreciate your help.

peter