Mortgage calculator

How to estimate a mortgage payment

Start with the home price and the percentage you plan to pay upfront. The amount left over is the loan principal. Enter the loan’s annual interest rate and term, then add your own estimates for yearly property tax and home insurance.

1. Use the interest rate from the loan offer. APR can include fees and is different from the interest rate used to calculate the payment. The example rate here is illustrative.
2. Enter annual tax and insurance amounts. The calculator divides each by 12. If you enter a monthly amount in these fields, the estimate will be too low.
3. Change one assumption at a time. Compare a different term, down payment or rate, and save each result on this device so you can return to it.

A mortgage example, step by step

This fixed example uses the calculator’s starting values in US dollars. It stays the same when you edit the calculator, so you can reproduce and check it.

Home price

$450,000.00

20% down payment

$90,000.00

Amount borrowed

$360,000.00

Principal & interest, 6.5% over 30 years

$2,275.44 / month

$4,500 tax + $1,500 insurance, divided by 12

$500.00 / month

Estimated monthly total

$2,775.44

The loan produces $459,160.16 in interest across 360 scheduled payments. The down payment is paid upfront; it is not part of the monthly payment or the “Total of all payments” result.

Compare the monthly payment and lifetime interest

For the same $360,000 principal and 6.5% rate, extending the term reduces each payment but increases the interest paid over the life of the loan. This isolates the effect of the term; real offers may use different rates for different terms.

Add $500 per month to each payment above for this example’s tax and insurance. The table’s total interest excludes those costs. A lower monthly payment alone does not tell you which loan has the lower overall cost.

What the mortgage results include

The principal-and-interest payment stays fixed in this model. Each month, interest is calculated on the remaining balance and the rest of that payment reduces the debt. The balance chart shows how much principal remains, not the property’s value or your equity.

The monthly total includes the tax and insurance amounts you entered. “Total of all payments” adds these same amounts across the whole term, even though actual taxes and premiums can change. The principal/interest bar compares only borrowing costs and excludes tax and insurance.

It does not model adjustable rates, balloon payments or extra repayments. The payoff month assumes the first monthly payment is one month from now; your lender’s schedule may differ.