About Loan Amortization Calculator

Build a full amortization schedule for any loan by specifying principal, annual interest rate, term in years, and payment frequency. The calculator uses the standard annuity formula to compute periodic payments, then iterates through every payment period showing principal, interest, remaining balance, and cumulative interest. Add an extra payment amount to see a side-by-side comparison of interest saved, time saved, and earlier payoff date.

• Six payment frequencies: monthly, biweekly (26/yr), weekly (52/yr), quarterly, semi-annual, and annual
• Loan-type templates with preset rates and terms for mortgage, auto, personal, student, business, and home equity loans
• Extra payment comparison shows interest saved, payments eliminated, and total savings
• Analysis tab displays principal-vs-interest ratio, interest-to-principal percentage, and effective annual rate
• Export the full schedule as CSV or copy to clipboard
• Optional monthly income input for debt-to-income context

Frequently Asked Questions

How does biweekly payment save money compared to monthly?

Biweekly means 26 payments per year (equivalent to 13 monthly payments instead of 12). That extra payment goes straight to principal, reducing total interest and shortening the loan. On a 30-year mortgage, this typically saves 4–6 years.

Does this account for variable interest rates?

No. It calculates a fixed-rate amortization schedule. For adjustable-rate loans, the schedule would change at each rate adjustment, which this tool does not model.