Mortgage Calculator

How this mortgage calculator works

This tool estimates a fixed-rate mortgage payment using the standard amortization formula. You enter the loan principal (how much you borrow), the annual interest rate, and the term in years. The calculator converts the annual rate to a monthly rate, multiplies the term by 12 to get the number of payments, then solves for the payment that pays the loan off in full by the final month.

What the result includes

The monthly figure is principal and interest only. It does not add property taxes, homeowners insurance, private mortgage insurance (PMI), HOA dues, or closing costs. Lenders often quote a larger “PITI” payment that bundles some of those items. If you need a budget number closer to reality, add those costs separately after you have the P&I estimate.

Formula

With monthly rate r (annual rate ÷ 100 ÷ 12) and n payments (years × 12), payment = P × [r(1+r)ⁿ] ÷ [(1+r)ⁿ − 1]. If the rate is zero, payment is simply principal ÷ n.

Worked example

Suppose you borrow $250,000 at 6.5% for 30 years. The monthly rate is about 0.5417%. Plugging into the formula gives a payment near $1,580. That is the amount that, repeated every month for 360 months, retires the loan under those assumptions. Total paid over the life of the loan is payment × 360 — much more than the original principal because of interest.

How to use it

1. Enter the loan amount you expect to finance (home price minus down payment, or your remaining balance if refinancing).
2. Enter the annual interest rate as a percent (for example, 6.5 for 6.5%).
3. Enter the term in whole years (15, 20, and 30 are common).
4. Read the estimated monthly payment and lifetime total, then try alternate rates or terms to compare scenarios.

Frequently asked questions

Why is my lender’s payment higher than this result?

This calculator shows principal and interest only. Taxes, insurance, PMI, and HOA dues are usually added on a loan estimate. Read our guide on mortgage payment vs PITI for a clear breakdown.

Does a larger down payment change the formula?

Yes — indirectly. Enter a smaller loan amount (price minus down payment). The formula itself is the same; the principal changes.

Can I model extra monthly payments?

Not on this page. Extra principal shortens the payoff schedule. Use the debt payoff calculator for a simple balance-and-payment timeline, or ask your lender for a custom amortization with curtailments.

Limitations

Real mortgages may have points, origination fees, adjustable rates, or biweekly payment schedules. This page assumes a fixed rate and monthly compounding. Results are estimates only and are not financial advice or a lender quote.

Results are estimates only and are not financial advice.