Mortgage Calculator
Calculate your monthly mortgage payment, total interest and loan breakdown for any home price, down payment and term.
Each payment covers interest plus a portion of the principal, so the loan is fully repaid by the end of the term.
That is 20.0% of the home price.
Monthly payment
$2,022.62
Loan amount
$320,000
80% loan-to-value
Total payment
$728,142
Over 360 months
Total interest
$408,142
Fully amortized — the balance reaches zero on the final payment.
How it works
M = P × r(1+r)ⁿ ÷ ((1+r)ⁿ − 1), with r = APR ÷ 12. Total payment adds monthly escrow = (annual tax + annual insurance) ÷ 12.
Example: $300,000 at 6.5% for 30 years → $1,896/month P&I; at $4,000 tax + $1,200 insurance → $2,330 total.
Last updated: August 2026
How this calculator is verified
Checked by True Calculator automated test suite on
- Formula verified against a published worked example in the automated test suite
- Edge cases (zero, negative, boundary and unit-mismatch inputs) covered by unit tests
The full verification method is on our how we verify page. Found an error? Tell us and we will re-check it.
When to Use This Calculator
Use this calculator when you are buying a home in the United States or comparing mortgage quotes — it is built for the US convention where the quoted rate and the monthly principal-and-interest payment are the headline numbers. NRIs buying property in the US, parents funding a child's US home purchase, and Indian professionals transferring for work all need the same figure: what a given home price, down payment and rate produce as a monthly payment. The tool separates the principal-and-interest payment from property tax and insurance, which lenders add to escrow separately, and comparing a 15-year and 30-year term shows the classic trade-off between a lower payment and lower total interest.
How to Use This Calculator
- Step 1: Enter the home price and the down payment, either as a percentage or an amount.
- Step 2: Enter the annual interest rate and the loan term in years, such as 30.
- Step 3: Read the monthly payment, which covers principal and interest only, before taxes and insurance.
- Step 4: Compare a couple of terms, such as 15 and 30 years, to see the trade-off between monthly payment and total interest.
Worked Example
A buyer considers a home priced at $400,000 with a 20% down payment of $80,000. Enter 400000 as the home price, 20 as the down payment percentage, 6 as the annual interest rate and 30 years as the term. The loan amount is $320,000 and the monthly principal and interest payment is about $1,919. Over 360 payments the total cost is about $690,682, of which roughly $370,682 is interest, so the 20% down payment avoids private mortgage insurance on top.
Tips and Common Mistakes
- •Tip 1: The 20% down payment threshold matters because loans below it usually carry private mortgage insurance.
- •Tip 2: Property taxes and homeowners insurance are separate from the principal and interest shown, so add them to estimate your real monthly outlay.
- •Tip 3: A 15-year term raises the monthly payment but cuts the total interest by roughly half in most rate scenarios.
- ✗Mistake 1: Entering the monthly rate as the annual rate, which makes the payment appear much smaller than it is.
- ✗Mistake 2: Forgetting that taxes and insurance are added by the lender to the escrow, so the full payment is higher than the tool's result.
Frequently Asked Questions
What is the mortgage formula this calculator uses?
It uses the standard amortising loan formula: M = P × r(1+r)ⁿ ÷ ((1+r)ⁿ − 1), where P is the loan amount, r the monthly rate (APR ÷ 12) and n the number of monthly payments.
Should I include property tax and insurance in the monthly payment?
Yes for a realistic budget. Enter your annual property tax and home insurance and the calculator adds them to the principal-and-interest payment so you see your true monthly housing cost.
Why does my monthly payment differ from my lender's quote?
Lenders may use a different rate, loan amount, term or add PMI, closing costs and escrow. Check which inputs your lender used and enter the same values here.
Is this mortgage calculator free to use?
Yes, True Calculator's mortgage calculator is completely free with no sign-up, no app install and no usage limits.
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