Mortgage Calculator
Estimate your monthly mortgage payment, total interest, and total cost for any home loan amount, rate, and term.
What is Mortgage Calculator?
A mortgage calculator shows your monthly principal-and-interest (P&I) payment on a home loan. Enter the home price, your down payment, the interest rate your lender quoted you, and the loan term to see how much you will pay each month and how much interest you will owe over the life of the loan.
Most American homebuyers choose a 30-year fixed-rate mortgage, but a 15-year fixed, 20-year fixed, or an adjustable-rate mortgage (ARM) can save you money in different ways. Run a few scenarios before you commit.
Formula
The standard fixed-rate amortization formula used by U.S. lenders is:
M = P × r × (1 + r)n ÷ ((1 + r)n − 1)
- M = monthly payment (principal & interest only)
- P = loan amount = home price − down payment
- r = monthly interest rate = APR ÷ 12 ÷ 100
- n = total number of monthly payments = years × 12
Worked example
A home priced at $400,000 with a $80,000 (20%) down payment financed at 6.75% APR over 30 years:
- Loan amount = $320,000
- Monthly rate = 0.0675 / 12 = 0.005625
- Number of payments = 360
- Monthly payment ≈ $2,076
- Total interest over 30 years ≈ $427,346
How to use this calculator
- Enter the full price of the home.
- Enter your down payment in dollars — 20% is typical if you want to avoid private mortgage insurance (PMI).
- Enter the APR your lender quoted. If you are shopping, try 6%, 6.5%, and 7% to see sensitivity.
- Enter the loan term — 30 years is most common; 15 years doubles the monthly payment but cuts total interest dramatically.
- Your monthly payment updates instantly.
This calculator shows principal and interest only. Your actual monthly housing payment will also include property taxes, homeowners insurance, HOA dues, and possibly PMI or mortgage insurance (MIP on FHA loans).
Frequently asked questions
What is included in my monthly mortgage payment?
A typical U.S. mortgage payment has four parts (PITI): Principal, Interest, property Taxes, and homeowners Insurance. If you put less than 20% down, private mortgage insurance (PMI) is usually added. FHA loans have a similar monthly mortgage insurance premium (MIP). This calculator shows P&I only — add taxes, insurance, and any HOA fees for your true monthly housing cost.
How much house can I afford?
A common rule of thumb is the 28/36 rule: keep your total housing payment (PITI) under 28% of your gross monthly income, and all debt payments combined under 36%. Lenders will often approve more, but just because you can borrow more does not mean you should.
Should I choose a 15-year or 30-year mortgage?
A 15-year loan has roughly a 50% higher monthly payment than a 30-year loan of the same amount, but you pay about one-third the total interest and build equity far faster. A 30-year gives you lower required payments and more flexibility — you can always make extra principal payments voluntarily.
What interest rate will I actually get?
The rate you qualify for depends on your credit score, the size of your down payment, the loan type (conventional, FHA, VA, jumbo), the property type, and overall market conditions. Published rates assume excellent credit (740+) and 20% down. Get quotes from at least three lenders.
What is PMI and how do I avoid it?
Private mortgage insurance protects the lender if you default. On conventional loans, it is required when your down payment is below 20%. Typical PMI costs 0.3%–1.5% of the loan amount per year. You can avoid it by putting 20% down, or remove it later once you have 20% equity in the home.