What is the Mortgage Calculator?
The Mortgage Calculator estimates your monthly principal-and-interest payment and the total interest you will pay over the life of the loan from the home price, down payment, rate and term you enter. With the optional fields it also builds a realistic "all-in" monthly cost once property tax, homeowners insurance and HOA dues are added on top.
How to Use This Calculator
- Enter the home price you are considering.
- Set your down payment as a percentage. The helper text shows the dollar amount and the resulting loan size.
- Enter the interest rate your lender quoted and pick a loan term.
- Add property tax, insurance and HOA if you want a full "all-in" monthly figure.
- Review the results. "Payment (P&I)" is principal and interest only; "Monthly all-in" adds taxes, insurance and HOA. The doughnut chart shows how much of every dollar you repay over the life of the loan is principal versus interest.
How does the underlying math work?
The monthly principal-and-interest payment comes from the standard amortizing-loan formula:
- M — monthly principal & interest payment
- L — loan amount = home price − down payment
- i — monthly interest rate = annual rate ÷ 12
- n — number of payments = term in years × 12
Total interest is (M × n) − L. Property tax is applied as a percentage of the home price and divided by 12; insurance and HOA are added directly to the monthly figure.
Real-world practical application
Buyers use it to sanity-check what a lender's pre-approval actually costs per month, to compare a 15-year term against a 30-year term before signing, and to see how much a larger down payment reduces lifetime interest. Current homeowners use the same numbers to judge whether refinancing at a lower rate is worth the closing costs.
Frequently Asked Questions
How much of a down payment do I need?
A 20% down payment lets you avoid private mortgage insurance (PMI) on a conventional loan. Conventional loans can go as low as 3–5% down, and FHA loans as low as 3.5%, but a smaller down payment means a larger loan balance, an added PMI premium, and more interest over the life of the loan.
What is included in my monthly mortgage payment?
Lenders call it PITI: Principal, Interest, property Taxes, and homeowners Insurance — the last two often collected in an escrow account. HOA dues and, if you put down less than 20%, PMI are on top of that. This calculator breaks out principal & interest and lets you add tax, insurance and HOA lines.
Should I choose a 15-year or 30-year mortgage?
A 15-year loan has a higher monthly payment but a lower rate and dramatically less total interest. A 30-year loan keeps the required payment low and flexible but costs far more over time. A common middle path is a 30-year loan with extra principal payments whenever your budget allows.
Related Calculators
- Debt Payoff Timeframe — see how extra payments shorten any loan.
- Compound Interest — what the down payment could earn if invested instead.
- Inflation Calculator — how a fixed mortgage payment shrinks in real terms over 30 years.