Mortgage Calculator - Monthly Payment, PITI & Amortization
Use this free mortgage calculator to estimate monthly principal, interest, taxes, insurance, and PMI payments with total interest breakdown.
Updated: • Free Financial Tool
Mortgage Calculator
Results
Principal & Interest: $2,075.51/mo
- 82% P&I
- 13% Taxes
- 5% Ins.
On a $400,000 home purchase with an $80,000 (20%) down payment and a 30-year fixed rate of 6.75%, your total monthly housing obligation is $2,528.85 (comprising $2,075.51 in principal and interest, plus $453.33 in taxes and insurance). Over 30 years, you will repay $427,185.01 in total interest on your $320,000 loan.
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What is a Mortgage Calculator?
A mortgage calculator estimates your monthly house payment on a home loan. It starts with principal and interest, then adds property taxes, homeowners insurance, and HOA dues so you can see the full monthly cost, often called PITI (principal, interest, taxes, and insurance).
Many buyers look only at the listing price or the principal and interest payment. Taxes and insurance can add hundreds of dollars a month, so it pays to include them from the start. Before you settle on a price range, check how much you can comfortably borrow with our home affordability calculator so your payment fits your income and other debts.
Common Ways to Use It
Budgeting Before You Make an Offer
See what your monthly payment would be before you bid on a home.
Comparing Loan Terms
Compare monthly payments and total interest for 15-year, 20-year, and 30-year loans.
Choosing a Down Payment
See how putting down 5%, 10%, or 20% changes your payment and whether you would need PMI.
Checking a Refinance
Estimate whether a lower rate would cut your payment enough to cover the cost of refinancing.
How the Mortgage Payment Formula Works
The monthly principal and interest payment on a fixed-rate mortgage uses the standard loan payment formula:
Monthly Payment Formula (Principal & Interest)
M = P × [ r(1 + r)^n ] / [ (1 + r)^n - 1 ]M: Monthly principal and interest payment
P: Loan amount (home price minus down payment)
r: Monthly interest rate (annual rate ÷ 12 ÷ 100)
n: Number of monthly payments (years × 12)
Lenders then add monthly amounts for property taxes and homeowners insurance to estimate your full payment. You will see these figures on the Loan Estimate required by CFPB Regulation Z (12 CFR § 1026.37).
Worked Example: $400,000 Home Purchase, 30-Year vs 15-Year
Both examples use a $400,000 purchase price, a 20% ($80,000) down payment, a 6.75% fixed rate, $4,000 a year in property tax and $1,440 a year in home insurance. For the 30-year loan, r = 0.0675 / 12 = 0.005625 and n = 30 × 12 = 360 months, so the compounding factor (1.005625)^360 ≈ 7.533245.
Worked examples
| 30-year fixed | 15-year fixed | |
|---|---|---|
| Loan principal (P) | $320,000 | $320,000 |
| Number of payments (n) | 360 | 180 |
| Monthly principal & interest | $2,075.51 | $2,831.71 |
| Monthly escrow (tax + ins.) | $453.33 | $453.33 |
| Total monthly payment | $2,528.85 | $3,285.04 |
| Total lifetime interest | $427,185.01 | $189,707.85 |
Good to know: The 15-year loan costs about $756 more each month but saves $237,477.16 in interest over the life of the loan.
To see how each payment splits between principal and interest month by month, use our mortgage amortization calculator.
Key Mortgage Terms to Know
1. PITI
Principal pays down your loan, and interest is the lender’s charge for lending you the money. Taxes and insurance are often collected monthly and paid for you through escrow.
2. Interest Is Front-Loaded
Interest is charged on the balance you still owe. Early payments go mostly to interest, and more goes to principal as the balance falls.
Watch out — PMI below 20% down: On a conventional loan, a down payment under 20% usually means paying PMI until your balance falls to 80% of the home’s original value.
3. Debt-to-Income Limits
Lenders compare your housing payment to your gross income (often 28% or less) and all your monthly debt payments to your gross income (often 36% to 43% or less).
To compare a 15-year and a 30-year loan side by side, try our mortgage comparison calculator.
How to Use This Mortgage Calculator
Follow these five steps to get a realistic estimate of your monthly housing cost:
1. Enter the Home Price and Down Payment
Enter the price you expect to pay and the cash you plan to put down. The calculator works out your loan amount and down payment percentage.
2. Choose a Loan Term
Pick 30, 20, or 15 years, or use a one-click preset, to see how the term changes your payment.
3. Enter Your Interest Rate
Use the rate a lender quoted or locked for you. Try rates 0.25% to 0.50% higher or lower with our mortgage rate calculator to see how much the rate matters.
4. Add Property Taxes and Insurance
Look up the property tax on your county’s tax records and get a homeowners insurance quote so these numbers match your area.
5. Review Your Results
Check the breakdown and the bar chart to see how much of each payment pays down your loan and how much goes to interest, taxes, and insurance.
Why It Helps to Run the Numbers First
Running the numbers before you sign a loan helps in four ways:
A Realistic Budget
Including taxes and insurance means no surprises when those bills show up after closing.
Less Interest Paid
Seeing your total interest can show how much extra payments would save. Try our mortgage extra payments calculator.
The Right Down Payment
Weigh keeping cash in savings against the monthly savings of putting 20% down and avoiding PMI.
Better Questions for Lenders
Knowing how your payment is built makes it easier to compare Loan Estimates and decide whether paying for discount points makes sense.
What Changes Your Payment and What This Tool Leaves Out
Four things can change your payment from one borrower or market to the next:
Your Credit Score
A higher credit score usually gets a lower rate. Lenders adjust pricing based on your score and down payment.
Loan Term
15-year loans usually have lower rates but higher monthly payments than 30-year loans.
Property Tax Changes
When your home is reassessed, your property tax and escrow payment can go up.
Insurance Costs
Homeowners and flood insurance premiums can rise with local weather risk and rebuilding costs.
What this calculator does not include:
- Closing costs: This tool shows your ongoing monthly payment, not one-time closing costs. These are often 2% to 5% of the purchase price and include lender fees, title insurance, and prepaid escrow.
- Rate changes before you lock: A quoted rate can change until you lock it with a lender. If you are thinking about refinancing, check how long it takes to break even with our mortgage refinance calculator.
Sources and References
The formula and terms on this page follow federal mortgage disclosure rules and public mortgage rate data:
CFPB TILA Regulation Z & Loan Estimate Guidelines 12 CFR § 1026.37
The federal rule that sets what lenders must show on the 3-page Loan Estimate, including your monthly payment, interest rate, and APR.
View Official CFPB Loan Estimate Guide
Freddie Mac Primary Mortgage Market Survey (PMMS)
Weekly national averages for 30-year and 15-year fixed mortgage rates. Use it to check whether the rate you enter is close to the current market.
Frequently Asked Questions (FAQ)
What is included in a monthly PITI mortgage payment?
Most mortgage payments have four parts, known as PITI: principal, interest, taxes, and insurance. Principal pays down what you borrowed, interest is what the lender charges, and property taxes and homeowners insurance are often collected monthly through an escrow account. HOA dues and PMI, if you have them, are added on top.
How much house can I afford with a standard mortgage?
Many lenders use the 28/36 rule as a starting point. Your total monthly housing payment (PITI plus HOA fees) should stay at or below 28% of your gross monthly income, and all your monthly debt payments together (mortgage, car loans, student loans, and credit cards) should stay at or below 36%. Some loan programs allow higher limits.
What is the difference between a 15-year and 30-year mortgage?
A 30-year fixed mortgage spreads repayment over 360 months, so each payment is lower, but you pay much more interest over the life of the loan. A 15-year mortgage has higher monthly payments, usually comes with a lower rate, and can save tens of thousands of dollars in interest.
How does my down payment percentage affect my monthly payment and PMI?
A bigger down payment means you borrow less, which lowers your monthly principal and interest. If you put down less than 20% on a conventional loan, lenders usually require private mortgage insurance (PMI). PMI typically costs about 0.2% to 1.5% of the loan amount per year, added to your monthly payment until you reach 20% equity and it is removed.
Why are mortgage interest payments front-loaded in the early years?
Each month's interest is based on the balance you still owe. In the early years your balance is at its highest, so most of each payment goes to interest. As the balance shrinks, less of each payment goes to interest and more goes to paying down the loan.
How do property taxes and homeowners insurance affect monthly escrow?
Many lenders set up an escrow account to pay your property taxes and homeowners insurance for you. They divide the yearly tax and insurance bills by 12 and add that amount to your monthly principal and interest payment. The escrow amount is reviewed each year and can go up or down when your tax bill or insurance premium changes.
