Mortgage Calculator
Estimate your monthly mortgage payment and the total interest you will pay over the life of the loan.
Last updated: June 18, 2026How is a monthly mortgage payment calculated?
Your monthly mortgage payment comes from the amortization formula: multiply the loan amount by the monthly interest rate and by (1 + monthly rate) raised to the number of payments, then divide by that same power minus one. It covers principal and interest only — property taxes, insurance and HOA dues are extra.
%
years
382,633.47
682,633.47
360
Formula
Examples
| Input | Result |
|---|---|
| $300,000 loan, 6% annual rate, 30-year term | Monthly payment $1,798.65; total repaid $647,514.57; total interest $347,514.57 |
| $250,000 loan, 5.5% annual rate, 15-year term | Monthly payment $2,042.71; total repaid $367,687.55; total interest $117,687.55 |
| $300,000 loan, 6% rate, comparing 30 vs 15 years | 30-year payment $1,798.65 with $347,514.57 interest; the 15-year term costs more per month but far less total interest |
About this calculator
A mortgage calculator estimates the monthly payment on a home loan and shows how much of your money goes toward interest over the life of the loan. A mortgage is a secured loan where the property itself serves as collateral, repaid in equal monthly instalments over a fixed term, typically 15 or 30 years.
The calculation uses the standard amortization formula, M = P × r × (1 + r)^n ÷ ((1 + r)^n − 1), where P is the loan principal, r is the monthly interest rate (the annual rate divided by 12), and n is the total number of monthly payments. Each payment covers the interest accrued that month first, with the remainder reducing the principal, so early payments are mostly interest and later ones are mostly principal.
To use this calculator, enter the loan amount (home price minus your down payment), the annual interest rate, and the loan term in years. The tool computes your fixed monthly principal-and-interest payment, the total amount you will repay, and the total interest cost. Adjust any field to compare scenarios instantly.
The monthly payment figure tells you the recurring cost, while total interest reveals the true price of borrowing. A 30-year loan lowers the monthly payment but dramatically increases lifetime interest compared with a 15-year term at the same rate. Use these results to judge affordability and to see how rate changes ripple through total cost.
A common mistake is treating the principal-and-interest figure as your full housing cost. Real ownership also includes property taxes, homeowners insurance, and possibly private mortgage insurance (PMI) or HOA dues, which can add hundreds per month. This calculator covers principal and interest only, so budget extra for those escrowed items before committing.
Frequently asked questions
No. It calculates only principal and interest, the core loan repayment. Property taxes, homeowners insurance, PMI, and HOA fees are separate costs usually bundled into your monthly escrow, so add those on top of the figure shown here when budgeting.
Interest is charged on the outstanding balance, which is highest at the start. With a large principal, the monthly interest portion is large and only a small slice reduces the balance. As the principal shrinks, the interest portion falls and more of each payment pays down the loan.
A lot. On a $300,000 loan at 6%, a 30-year term costs about $347,515 in total interest, while a 15-year term at the same rate costs far less because the balance is repaid much faster. The monthly payment is higher, but lifetime interest drops sharply.
Extra payments go straight to principal, shrinking the balance faster and reducing future interest. Even one extra payment a year can shave years off a 30-year mortgage. This calculator shows the standard schedule, so use it as a baseline before factoring in prepayments.
Yes, it assumes a fixed rate for the entire term. Adjustable-rate mortgages (ARMs) change after an introductory period, so their payments will differ. For an ARM, estimate the initial fixed-rate period and recalculate when the rate resets.
Your down payment reduces the loan principal you enter here. A larger down payment means a smaller loan, lower monthly payments, and less total interest. It can also help you avoid PMI if you put down at least 20% of the home price.
Sources & references
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