Mortgage Calculator - Payment and Amortization

It uses the standard amortization formula: M = P times r divided by 1 minus (1 plus r) to the power of minus n, where P is the loan amount, r is the monthly interest rate (annual rate divided by 12), and n is the number of months. Taxes, insurance, PMI, HOA and other costs are added on top to show your full monthly out-of-pocket amount.

Private mortgage insurance is usually required when your down payment is under 20 percent. This calculator adds PMI each month until the loan balance falls to 80 percent of the home price, then removes it automatically, just as a lender would.

An extra amount each month is applied entirely to the principal. That lowers the balance faster, so less interest builds up and the loan is paid off sooner. Try adding an extra payment and watch the payoff date and total interest drop.

No. The calculator runs entirely in your browser. Your numbers never leave your computer, and it works offline once the page has loaded.

It shows how each payment splits between interest and principal over time, and how the balance falls. Early payments are mostly interest, while later payments are mostly principal. You can switch between an annual summary and the full monthly schedule, and export it as a CSV.

The math works for any currency. Amounts are shown with a dollar sign, but the payment, schedule and totals are correct whatever currency you are budgeting in.

This calculator assumes a fixed interest rate for the whole term, which covers most home loans. For an adjustable-rate mortgage you can re-run it with the new rate once it changes.