Mortgage Calculator
Estimate principal-and-interest from price, down payment, rate, and term. Every assumption and formula shown — free, private, no account needed.
Added Apr 18, 2026 · Updated May 1, 2026
Scenario A
Input
Result
Enter a value for home price to see your result.
How it works
Calculates the fixed monthly mortgage payment for a home purchase given the home price, down payment, interest rate, and loan term. Uses the standard amortization formula to show total cost and interest over the life of the loan.
Formula
Monthly = P × r / (1 − (1 + r)^(−n))
- P
- Loan principal (home price minus down payment)
- r
- Monthly interest rate (annual rate ÷ 12 ÷ 100)
- n
- Total number of monthly payments (years × 12)
Step by step
- 01Subtract the down payment from the home price to get the loan principal.
- 02Convert the annual rate to a monthly rate by dividing by 12 and 100.
- 03Multiply the term in years by 12 to get the number of monthly payments.
- 04Apply the amortization formula to find the fixed monthly payment.
- 05Multiply the monthly payment by the total number of payments to get the total paid, then subtract the principal to get total interest.
Examples
$350k home, $70k down, 6.5%, 30 years
A $280,000 mortgage at 6.5% over 30 years has a monthly payment of ~$1,770. You pay roughly $357,000 in interest over the life of the loan.
Inputs
- Home price:
- 350000
- Down payment:
- 70000
- Annual interest rate:
- 6.5
- Loan term:
- 30
Result
- Monthly payment:
- 1769.79
- Total paid:
- 637124.57
$300k home, $60k down, 5%, 15 years
A 15-year term is more expensive monthly but saves substantial interest compared to 30 years.
Inputs
- Home price:
- 300000
- Down payment:
- 60000
- Annual interest rate:
- 5
- Loan term:
- 15
Result
- Monthly payment:
- 1897.9
- Total paid:
- 341622.85
Frequently asked questions
What is not included in this mortgage calculator?
This calculator shows principal and interest only. Your actual monthly payment will also include property taxes, homeowner's insurance, and possibly PMI (private mortgage insurance) if your down payment is less than 20%.
How much does a lower interest rate save?
On a $300,000 loan, dropping from 7% to 6% saves about $190/month and over $68,000 in total interest over 30 years. Even small rate differences matter significantly over a long term.
Is the monthly payment the same every month on a fixed-rate loan?
Principal-and-interest on a standard fixed-rate amortizing loan is level each month. If your bank statement changes, it is usually because taxes, insurance, or PMI are billed through escrow, not because the loan math changed.
Can I rely on this number for a refinance or purchase offer?
Use it for planning and comparing scenarios. Your lender's Loan Estimate will include APR, points, fees, and underwriting rules that can shift the payment; treat this tool as a ballpark, not a binding quote.
Why might my lender's payment differ by a few cents?
Rounding per period, day-count conventions, and how partial first months are handled can create tiny differences from textbook amortization. Differences of a few cents are normal.