Mortgage Calculator
Estimate monthly mortgage payments with taxes and insurance.
How this calculator works
Formula
M = P · r(1+r)^n / ((1+r)^n − 1)
Method
Uses the standard amortization formula with monthly compounding, plus a proportional split of yearly property taxes and insurance.
Example
A $320,000 loan at 6.5% for 30 years costs about $2,023/month before taxes and insurance.
The complete guide to the Mortgage Calculator
A mortgage calculator turns the biggest number in most people's lives — a home loan — into a monthly payment you can actually plan around. Below we walk through exactly how the math works, what changes your payment, and how to use the Morecalcs tool above to test scenarios in seconds.
What the mortgage calculator computes
Enter your home price, down payment, interest rate, term, and yearly property tax and insurance. The tool returns your monthly principal-and-interest payment, the escrow amount for tax and insurance, the total interest you'll pay across the loan, and the grand total paid over the life of the mortgage. This is the same PITI figure your lender will quote you.
The math behind every fixed-rate mortgage
The core amortization equation is M = P · r(1+r)^n / ((1+r)^n − 1), where P is the loan amount, r is the monthly interest rate (annual ÷ 12), and n is the total number of monthly payments. On a $320,000 loan at 6.5% for 30 years, that produces a $2,023 monthly PI payment. Add roughly $400 for taxes and insurance on a typical U.S. home and you land near $2,420 all-in.
Down payment: the invisible interest saver
Every additional dollar of down payment removes a dollar from the loan and eliminates its interest across 30 years. Going from 10% down to 20% down on a $400,000 house also removes PMI (private mortgage insurance), which typically costs 0.5–1.5% of the loan per year — another $150–$400 per month.
Interest rate and term: the two big levers
A one-percentage-point drop in rate saves roughly $200 per month on a $320,000 loan. Shortening the term from 30 to 15 years raises the monthly payment by about 40% but slashes total interest by more than 60%. Use the calculator to test both directions.
Property tax and homeowner's insurance
Both are typically escrowed, meaning your lender collects 1/12 of the annual bill each month and pays it for you. Skipping these numbers hides a big part of your true housing cost. Look up the local millage rate for tax and get one insurance quote before you plan around a payment.
The value of extra principal payments
Adding just $150 to each payment on that same $320,000 loan trims about 6 years off the term and saves roughly $85,000 in interest. The reason is compounding in reverse — every dollar of extra principal today skips 30 years of interest accrual.
When refinancing actually helps
The rule of thumb: refinance only if the new rate is at least 0.75 point lower and you'll stay in the home long enough for the closing costs to be recovered by the monthly savings. Divide closing costs by monthly savings — that's your break-even in months.
Common mistakes the calculator catches
Buyers routinely forget to budget for HOA fees, maintenance (rule of thumb: 1% of home value per year), and closing costs (2–5% at purchase). Use the tool to model the real number, not the marketing number in a listing.
Frequently asked questions
Does this calculator include PMI?
PMI isn't included by default. If your down payment is below 20%, add roughly 0.5–1.5% of the loan amount as an annual PMI cost to the insurance field to see the true monthly.
Fixed or adjustable rate?
This calculator assumes a fixed rate. For an ARM, use the initial rate for the fixed period and re-run for the maximum possible rate to see the worst case.
Is the total interest figure accurate?
Yes — it's the sum of every scheduled interest payment across the term, given the inputs. Extra payments would reduce this.