Loan Amortization Calculator

It is a month-by-month table of every payment on a fixed-rate loan, showing how much goes to interest, how much goes to principal and what you still owe afterward. Early payments are mostly interest because the balance is large. As the balance falls, more of the same payment goes to principal. The schedule also shows your payoff date and the total interest you will pay over the life of the loan.

The calculator uses the standard amortization formula: payment = P x r / (1 - (1 + r)^-n), where P is the loan amount, r is the APR divided by 12 and n is the number of months. The payment is rounded to the cent, and the final payment is adjusted so the balance ends at exactly $0. At 0% the payment is simply the loan amount divided by the number of months.

Every extra dollar goes straight to principal, so it stops being charged interest from that month on. On a $350,000, 30-year mortgage at 6.5%, an extra $200 a month saves about $108,000 in interest and pays the loan off about 6 years early. Add a scenario with your own numbers to see the exact payoff date, months saved and interest saved next to your baseline.

Biweekly means paying half of your monthly payment every 14 days, starting on your first payment date. That adds up to 26 half-payments, or 13 full payments, a year. The calculator counts how many half-payments land in each calendar month (2 or 3) and charges interest monthly on the balance, which is how most US mortgages accrue interest. Ask your lender how it credits biweekly payments before you sign up.

Dollar for dollar, money paid earlier saves more interest because it removes principal for more months. A $10,000 lump sum today beats $10,000 spread over the next few years. But a steady extra monthly amount is often easier to keep up and adds up to far more over time. Model both as scenarios and compare the interest saved and payoff date side by side.

Paying extra earns a guaranteed return equal to your interest rate. Investing may earn more over long periods but with risk. High-rate debt (above about 7% to 8%) usually wins for paying down; low-rate mortgages are a closer call. Keep an emergency fund and any employer retirement match first. The Pay Down Mortgage or Invest calculator compares the two paths directly.

It assumes a fixed rate and monthly interest. It does not include property taxes, insurance, PMI, HOA dues or escrow, variable or adjustable rates, prepayment penalties, or fees. Some lenders apply extra payments differently or hold them until the next due date. Use the schedule as a planning tool and confirm exact figures with your lender or loan statement.

Yes, on this device only. Your loan and scenarios are saved in your browser automatically, with no account or sign-in. Use Clear saved to reset to the defaults. Copy link creates a link with your numbers in it, so you can open the same plan on another device or share it with a partner or advisor.