Business in Leasing and Lending industry widely uses   legacy tools or Calculators to calculate Payment Schedule or Amortization Schedule for the equipment they lease or for the Amount they lend.  With Cloud (SaaS) enablement catching up in these industries, Business in Leasing, Lending and Mortgage industry uses Salesforce.com to manage their customers, Sales and Quoting Process. However they are not completely migrated to Cloud (SaaS) still this Industry specific users use Legacy Tools and Calculators which are on Premise or a App Installed on their Desktop. To calculate the Payments they have to use other tools to calculate the Payment/Amortization Schedule and manually key in the Calculated values on Quote in Salesforce.com to create Quotes.

When my customer asked me if I could help on this . I started my research to find if there are any apps in appexchange that can do the Amortization calculation.  My extensive research went in vain, Then we decided to build a Calculator on Force.com and Link to Quote Record so that it can be launched from a quote and calculated values can go back to quote and used for PDF generation.

The Amortization Calculator tool also does calculations for  

Even and Uneven Payments.

Ability to Calculate two Amortization for Two different interest rates This feature gives the ability to calculate the Buy down Amount and Buy down Percentage.

Advance Vs. Arrears Payments.

Accrued Interest Calculation.

Compounding of Interest (Monthly, Quarterly, Half yearly, Annually).

Payment Options (Monthly, Quarterly, Half yearly, Annually).

360 Vs. 365 Days in Calendar.

Implied Lease Rate Factor Promo.

Display the complete Amortization Schedules.

Lets Understand Amortization  (Sourced from Wikipedia)

What is Amortization?  

In lending, amortization is the distribution of payment into multiple cash flow installments, as determined by an amortization schedule. Unlike other repayment models, each repayment installment consists of both principal and interest. Amortization is chiefly used in loan repayments (a common example being a mortgage loan). Payments are divided into equal amounts for the duration of the loan, making it the simplest repayment model. A greater amount of the payment is applied to interest at the beginning of the amortization schedule, while more money is applied to principal at the end. Commonly it is known as EMI or Equated Monthly Installment.

A is the periodic amortization payment

P is the principal amount borrowed

r is the periodic interest rate divided by 100

n is the total number of payments

Apex doesn’t support financial Functions or methods to calculate Payment value as Excel has PMT () function, The Formula have to  be programmed in Apex.