Mortgages
Mortgage Calculator
Estimate your monthly principal and interest payment, plus total interest and total cost, based on your home price, down payment, interest rate, and loan term.
Full breakdown
Amortization schedule
Every payment from your first month to payoff, showing how much goes to interest vs. principal.
How this calculator works
This calculator uses the standard fixed-rate amortization formula, the same one lenders use to calculate a level monthly payment that pays off your loan by the end of its term. Each month, part of your payment covers interest on the remaining balance, and the rest reduces your principal. Early in the loan, more of the payment goes to interest; later, more goes to principal.
The formula
Where:
- M — monthly principal & interest payment
- P — loan principal (home price minus down payment)
- r — monthly interest rate (annual rate ÷ 12)
- n — total number of monthly payments (years × 12)
If your rate is 0%, the formula above isn't used — the loan amount is simply divided evenly across every remaining month.
Example calculation
$400,000 home, 20% down, 6.5% rate, 30-year term
- Loan amount (P)
- $320,000
- Monthly rate (r)
- 0.5417%
- Number of payments (n)
- 360
- Monthly payment (M)
- $2,022
Factors that affect your result
A larger down payment lowers your loan amount, which lowers both your monthly payment and your total interest.
Even a small rate change has a large effect over a 30-year term — try adjusting the rate by 0.5% to see the impact.
A shorter term (like 15 years) means a higher monthly payment but dramatically less interest paid overall.
Frequently asked questions
Does this mortgage calculator include property taxes and insurance?
By default, this calculator shows principal and interest only. Checking "Include taxes & other costs" lets you add property tax, homeowners insurance, PMI, HOA fees, and other costs to see your full estimated monthly housing payment alongside the principal-and-interest figure.
How do extra payments affect my mortgage?
Extra payments — monthly, annual, or a one-time lump sum — go entirely toward your principal balance, so they shorten your payoff date and reduce your total interest without changing your required monthly payment. Advanced Options shows the new payoff date and total interest saved once you add one.
What down payment should I use?
Enter whatever down payment you're actually planning to make. Conventional loans often start around 3-5% down, while 20% down avoids PMI on most conventional loans. Try a few amounts to see how it changes your payment.
How accurate is this calculator?
The math uses the standard fixed-rate amortization formula lenders use for principal and interest, so it's accurate for that portion. Your actual lender quote may differ because it can include taxes, insurance, PMI, HOA dues, and rate variations based on your credit profile.
What happens if I enter a 0% interest rate?
The calculator switches to simple division: your loan amount is split evenly across every month of the term, with no interest charged.
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This calculator is for educational purposes only and does not constitute financial, tax, or legal advice, or a loan offer. Actual rates, terms, and payments are set by individual lenders and depend on factors this calculator does not account for, including credit history, taxes, insurance, and loan program.