Mortgage Calculator
Estimate the monthly cost of a mortgage from the home price, the down payment, the interest rate and the term. Property tax and insurance can be included, and an extra monthly payment shows how many years and how much interest you could save.
1 to 50.
Goes straight to the principal.
Result
Enter the home price, the down payment, the rate and the term.
The calculation runs in this browser tab. Nothing you enter is uploaded, saved or logged.
What goes into a monthly mortgage payment?
A mortgage is a loan secured on a home. The amount borrowed is the home price minus the down payment. The core of the payment is principal and interest, worked out like any fixed-rate loan: on 280,000 at 6.5% over 30 years it is 1,769.79 a month. Over the whole term the borrower pays 637,125 on that loan, of which 357,125 is interest, more than the loan itself.
Owners also pay property tax and home insurance, often collected monthly with the mortgage payment and in that case divided by twelve. On a 350,000 home, a property tax of 1.1% a year and insurance of 1,200 a year add 320.83 and 100.00 a month, for a total of 2,190.62. The down payment as a share of the price (here 20%) is the opposite of the loan-to-value ratio, which lenders use to judge risk.
How to use the Mortgage Calculator
- Enter the home price and the down payment, as a percentage of the price or as an amount.
- Enter the yearly interest rate and the loan term in years.
- Optionally enter the yearly property tax as a percentage of the price, the yearly home insurance, and an extra monthly payment.
- Read the total monthly payment and its parts, the total interest, and follow the balance year by year in the table.
Formula
- Loan amount
- loan = home price − down payment
- Principal and interest
- M = L × i ÷ (1 − (1 + i)^−n), with i = annual rate ÷ 12 and n = years × 12
- Property tax and insurance
- monthly = yearly amount ÷ 12
- Total payment
- principal and interest + property tax + insurance
Each month the interest is the balance times the monthly rate. The rest of the payment reduces the balance, so the share going to principal rises over the years. An extra payment goes to principal in full.
The payment is rounded to the cent, as is the interest each month, and the last payment is adjusted to clear the balance.
Worked example
A 350,000 home with a 20% down payment, 6.5% over 30 years, property tax of 1.1% and insurance of 1,200 a year. These are the results the calculator gives:
| Question | Result |
|---|---|
| Input: Home price | 350000 |
| Input: Down payment | 20 |
| Input: Down payment is | A percentage of the price (%) |
| Input: Annual interest rate | 6.5 % |
| Input: Loan term in years | 30 |
| Input: Property tax per year (optional) | 1.1 % of the price |
| Input: Home insurance per year (optional) | 1200 |
| Total monthly payment | 2,190.62 |
| Principal and interest | 1,769.79 |
| Property tax | 320.83 |
| Home insurance | 100.00 |
| Loan amount | 280,000.00 |
| Down payment | 70,000.00 (20.0%) |
| Total interest over the loan | 357,125.12 |
| Total paid on the loan | 637,125.12 |
Assumptions and limits
- This is a fixed-rate, fully amortising mortgage with interest at one twelfth of the annual rate each month, as is standard in the United States. Other countries use other conventions: for example, fixed-rate mortgages in Canada are quoted with semi-annual compounding. Your lender’s figures prevail.
- Mortgage insurance, closing costs, association fees, utilities, maintenance and changes in taxes or in the rate are not included.
- Property tax is entered as a percentage of the home price and kept constant. Real property taxes are set locally and can change.
- Terms are limited to 50 years. These results are a calculation from the numbers you enter, not financial advice.
Frequently asked questions
How do I calculate a mortgage payment?
Subtract the down payment from the price to get the loan, then use M = L × i ÷ (1 − (1 + i)^−n), where i is the annual rate ÷ 12 and n the number of months. For 280,000 at 6.5% over 360 months that gives 1,769.79, before tax and insurance.
How much house can I afford?
That depends on your income, debts and the lender’s rules, which the calculator does not know. Enter several prices to see how the monthly cost changes, and compare the total payment with your budget.
How much does a bigger down payment save?
It lowers the loan, so the payment and the total interest fall in proportion. On this home, putting down 30% instead of 20% reduces the loan from 280,000 to 245,000, and the principal and interest payment by about 221 a month.
How much can extra payments save?
A lot, because they cut the balance on which interest is charged. An extra 150 a month on the 280,000 loan pays it off about 5 years 11 months early and saves about 82,470 of interest.
Why is the total interest so high on a 30-year loan?
Interest is charged every month on the remaining balance, which stays high for many years. At 6.5% over 30 years the interest is more than the amount borrowed. A shorter term has a higher payment but much less interest.
Are property tax and insurance part of the mortgage?
Not strictly, but many lenders collect them with the payment and pay them for you. The calculator shows them separately so you can see the principal and interest on their own and the total.