Monthly Mortgage Payment Calculator
Estimate the monthly principal-and-interest payment from the home price, down payment, interest rate and loan term.
Mortgage Calculator
A mortgage calculator turns four numbers — home price, down payment, interest rate and loan term — into the one number most home shoppers actually want: the monthly principal-and-interest payment. It's built for quick comparisons while you're weighing options, not as a substitute for a lender's official quote.
How does a mortgage calculator work?
This calculator uses the standard amortization formula: monthly payment = P × r(1+r)ⁿ ÷ ((1+r)ⁿ − 1), where P is the loan amount (home price minus down payment), r is the monthly interest rate, and n is the total number of monthly payments over the loan term. Enter the home price, down payment, annual interest rate and term, and it solves that formula instantly — the same math a lender uses internally, just without the paperwork.
Comparing a 15-year term against a 30-year term
Run the same home price and rate through both terms side by side. A 15-year mortgage carries a noticeably higher monthly payment but pays off the loan in half the time and costs far less in total interest, since less of the balance sits accruing interest for as long. A 30-year mortgage spreads the same loan into a smaller, more manageable monthly payment, but the trade-off is a much larger amount paid in interest over the life of the loan. Neither term is universally the better choice — it comes down to whether your budget favors a lower monthly payment now or a lower total cost over time.
Why a bigger down payment moves the needle
Increasing the down payment shrinks the loan amount directly, which lowers both the monthly payment and the total interest — try raising it in the calculator and watch how quickly the payment drops. Beyond the math, a down payment of 20% or more on a conventional loan usually also avoids private mortgage insurance (PMI), an extra monthly cost lenders add when the down payment is smaller, which this calculator doesn't include but is worth budgeting for separately.
What's the difference between principal and interest, and how much interest will you actually pay?
Principal is the amount you borrowed; interest is what the lender charges for lending it, calculated as a rate applied to whatever balance remains. Early in the loan, most of each payment goes toward interest because the balance is still high; later payments shift increasingly toward principal as the balance shrinks — this shifting split is called amortization. Total interest paid over the life of the loan depends on the amount borrowed, the rate, and the term: a longer term spreads payments out but adds up to more interest overall, even though each individual payment is smaller.
Does paying extra toward the principal actually save money?
Yes. Any payment beyond the required monthly amount that's applied directly to principal reduces the balance interest is calculated on for every remaining month of the loan, which can meaningfully cut both the total interest paid and the time left on the loan — even modest extra payments made consistently add up over years.
What this estimate leaves out
This calculator estimates principal and interest only — it doesn't include property taxes, homeowners insurance, PMI or closing costs, all of which a lender would add to your actual monthly payment. It's also not an official loan quote: use it to compare scenarios and narrow down what you can plan for, then confirm real numbers with a lender before making a decision.
So how much house can you actually afford?
Affordability depends on more than the loan math above — your income, existing debt payments, down payment size, credit profile and the lender's own requirements all factor in. A commonly used guideline caps total housing costs (payment, taxes and insurance combined) around 28% of gross monthly income, but the calculator's payment output is the fastest way to see whether a given price range fits comfortably before you get further into the process.
Where does the word "mortgage" come from?
The word itself is nearly 650 years old: "mortgage" entered English in the late 1300s from Anglo-Norman French "mort gage" — literally "dead pledge," combining the Latin-rooted "mort" (dead) with "gage" (pledge). The name reflects how the pledge dies either way: if the loan is repaid, the lender's claim on the property dies; if the borrower defaults, their claim to the property dies instead. For most of that history, mortgages didn't work anything like today's calculator assumes — before the 1930s, U.S. home loans were typically short-term, interest-only "balloon" loans lasting just 3 to 5 years, with the full principal due in one lump sum at the end, so borrowers had to refinance repeatedly just to stay in their homes. The fully amortizing loan this calculator models — steady payments that pay down both principal and interest over a fixed term — didn't exist in the U.S. mortgage market until the Federal Housing Administration was created in 1934 during the Great Depression, insuring lenders against default so they could offer longer, safer, fully amortized loans; its earliest standard terms ran 15 to 20 years. The 30-year term specifically arrived later: Congress authorized it for new construction in 1948, then extended it to existing homes in 1954, which is when it became the mainstream option it still is today.
Is Mortgage Calculator free to use?
Yes. Mortgage Calculator is completely free, with no sign-up and no usage limits.
Do I need to install any software?
No. Mortgage Calculator runs directly in your web browser — nothing to download or install.
Is my data kept private?
Everything happens on your device. We never receive or store the file or text you enter into Mortgage Calculator.