Mortgage Calculator
The number your lender quotes is never the whole number. Taxes, insurance, and mortgage insurance ride along with principal and interest, and a small extra payment each month can quietly shave years off the loan. This calculator puts all of it in one place, so you can compare scenarios before you sign anything.
Buying a home is usually the biggest loan most people ever take on. The monthly figure matters, but so do the payoff date and the total interest, and those are the numbers this page works through.
Enter your numbers
Result
Run your own numbers below, then try a second scenario to compare.
What to type in, and why
Loan amount. Enter the amount you are borrowing — the principal the payment is calculated on.
Rate and term. Use the rate your lender quoted, and pick 30, 20, or 15 years, or type a custom term.
Taxes, insurance, and PMI. Yearly property tax and homeowners insurance go in here, plus PMI if your down payment is under 20%. Together with principal and interest they make up PITI, the real monthly cost.
Extra payments. Add an extra monthly payment and watch the payoff date move closer and total interest fall.
The formula behind it
For a fixed-rate mortgage, the principal-and-interest part of the monthly payment is:
M = P × r × (1 + r)n ÷ ((1 + r)n − 1)
- M = monthly principal-and-interest payment
- P = loan amount (the principal you borrow)
- r = monthly interest rate (yearly rate ÷ 12)
- n = total number of monthly payments (years × 12)
Your full monthly payment is usually PITI: principal + interest + property taxes + homeowners insurance. If your down payment is below 20%, PMI (private mortgage insurance) is often added on top. Taxes and insurance are typically held in escrow and paid by your lender from that account. Note the difference between the interest rate and the APR: the APR folds in lender fees, so it is usually slightly higher than the rate and is the better number for comparing loan offers.
One loan, worked through
Loan amount $300,000, fixed rate 6.5% per year, term 30 years, no taxes, insurance, or PMI in this example.
| Step | The math |
|---|---|
| Monthly rate | r = 0.065 ÷ 12 = 0.00541667 |
| Number of payments | n = 30 × 12 = 360 |
| Growth factor | (1 + r)n = (1.00541667)360 = 6.991798 |
| Monthly payment | M = 300,000 × 0.00541667 × 6.991798 ÷ (6.991798 − 1) = $1,896.20 |
| Total paid over 30 years | $1,896.20 × 360 = $682,633.47 |
| Total interest | $682,633.47 − $300,000 = $382,633.47 |
With an extra $200 per month: paying $2,096.20 a month clears the same loan in 277 months (23 years and 1 month) instead of 360. Total interest falls to $279,184.67, a saving of $103,448.79. That is the payoff effect this calculator shows. All figures rounded to the nearest cent.
What the result is really telling you
The headline number is your monthly payment, but the payoff date matters just as much. It is when the loan ends if you keep paying the same amount, and extra payments pull it forward.
Then there is total interest: what the loan costs beyond the amount you borrowed. A shorter term or extra payments shrink this fast.
And there is how payments split over time. Early payments are mostly interest; over time, more of each payment goes to principal. Extra payments shorten the payoff time and cut total interest.
Assumptions worth knowing
| Assumption | What it means for your result |
|---|---|
| Fixed rate | The rate stays the same for the whole term. Adjustable-rate mortgages (ARMs) change, so this estimate covers the fixed period only. |
| On-time payments | No missed or late payments, no late fees. |
| No fees in the payment | Closing costs, points, and lender fees are not included unless you add them to the loan amount. |
| Taxes and insurance as entered | Property tax and insurance can rise over time; the estimate uses the figures you enter. |
| PMI until 20% equity | PMI usually drops once you reach 20% equity, but rules vary by loan type. Check your loan terms. |
Two more ways to run it
$450,000 loan, 6% fixed, 30 years: $2,697.98 per month for principal and interest, $521,271.85 total interest.
$250,000 loan, 5.5% fixed, 15 years: $2,042.71 per month for principal and interest, $117,687.55 total interest. The payment is higher than a 30-year loan, but total interest is far lower.
Biweekly payments: paying half your monthly payment every two weeks gives you 26 half-payments a year, the same as 13 monthly payments. That one extra payment a year shortens a 30-year loan by roughly 4 years.
Questions, answered
How do extra mortgage payments affect my payoff?
Extra payments go straight to principal, which shrinks the balance that interest is charged on. Even $200 a month on a $300,000 loan at 6.5% pays it off about 7 years early and saves over $100,000 in interest. Use the calculator to test your own amount.
What does PITI mean?
PITI stands for principal, interest, taxes, and insurance, the four parts of a typical monthly mortgage payment. Lenders use PITI when they check whether you can afford the loan, so it is a more honest monthly figure than principal and interest alone.
What is PMI, and when do I pay it?
PMI is private mortgage insurance. Lenders usually require it on conventional loans when the down payment is under 20%. It protects the lender, not you, and it is added to your monthly payment. It typically ends once your loan balance falls to 80% of the home’s value, but the exact rules depend on your loan type.
Is a 15-year or 30-year mortgage better?
A 15-year loan has a higher monthly payment but far less total interest. A 30-year loan has a lower payment and more flexibility, but you pay much more interest over time. The right choice depends on your budget and how long you plan to stay in the home. Run both terms in the calculator and compare total interest, not just the monthly payment.
What is the difference between the interest rate and the APR?
The APR folds in lender fees, so it is usually slightly higher than the rate. For comparing loan offers, the APR is the better number, because it reflects more of what the loan actually costs.
If this wasn’t quite the one
A home loan is one kind of borrowing. The Loan Calculator runs the same math for auto and personal loans, the Compound Interest Calculator shows what savings do over the same years, and the Savings Goal Calculator works out the monthly deposit for a down payment. The Percentage Calculator handles down payment percentages and rate changes, and the Retirement Calculator shows how today’s mortgage choice sits beside long-term savings. Two guides go deeper: How to Calculate a Mortgage Payment, and How Much Mortgage Can I Afford. Or browse All Finance Calculators and All Calculators.
This calculator is for general information and planning only. It is not financial, investment, tax, or legal advice, and it is not a loan offer or a guarantee of any rate or approval. Mortgage terms, taxes, insurance, and PMI vary by lender, location, and loan type, so check the figures with a qualified professional or your lender before you decide.
Where this comes from
- Consumer Financial Protection Bureau (CFPB), mortgage and home-buying guidance, including PITI, PMI, and amortization concepts.
- U.S. Federal Reserve, general information on mortgage rates and lending.