Monthly payment, total interest, payoff time, and a full amortization breakdown — all in your browser, instantly.
| Year | Principal paid | Interest paid | Remaining balance |
|---|
This free loan and mortgage calculator gives you everything you need to understand a fixed-rate loan before you sign. Enter your loan amount, down payment, interest rate, and term — you get your monthly payment, the total interest you'll pay over the life of the loan, and a visual split showing how much of your money goes to principal versus interest.
The calculator uses the standard amortization formula: M = P × r × (1+r)n ÷ ((1+r)n − 1), where P is the financed principal (loan amount minus down payment), r is the monthly rate (APR ÷ 12 ÷ 100), and n is the number of payments (term × 12). At 0% interest, the monthly payment is simply the principal divided by the number of months. The calculation runs month by month in your browser — no server involved.
Every dollar of extra payment goes directly to reducing your principal. A lower principal means less interest accrues the following month, which accelerates payoff in a compounding way. On a typical 30-year mortgage at 6.75%, adding just $200/month can cut roughly 5–6 years off your loan and save tens of thousands in interest. The calculator runs a second full amortization without the extra payment to give you the precise comparison.
The underlying math is identical whether you're calculating a 30-year mortgage, a 5-year car loan, a personal loan, or a student loan. Fixed-rate means your payment is the same every month; this calculator handles all of those. It does not handle variable-rate or adjustable-rate loans where the rate changes over time.