Mortgage Calculator

A mortgage is the largest loan most people ever take, and small changes in rate or term move the total cost by tens of thousands. This mortgage calculator shows the monthly principal-and-interest payment, the loan amount after your down payment, and the total interest over the full term.

Use it to test scenarios before you talk to a lender: a larger down payment, a shorter term, or a slightly lower rate.

Enter valid values to see the results.

Formula

Payment = (Price − Down) × r / (1 − (1 + r)⁻ⁿ), where r = rate ÷ 12, n = months

The payment shown is principal and interest only. Real mortgage payments often also include property tax, insurance and, with small down payments, mortgage insurance — add those to budget the true monthly cost.

What you need

Home price: the agreed purchase price, not the listing price.
Down payment: cash you pay upfront. 20% is the classic threshold that avoids mortgage insurance in many countries.
Rate and term: use the fixed annual rate and full term from the loan offer — 30 and 15 years are the most common.

Worked example

A $350,000 home with $70,000 down at 6.5% for 30 years: the loan is $280,000, r ≈ 0.005417, n = 360. Payment ≈ $1,769.80 per month. Total paid over 30 years ≈ $637,128, so interest alone is about $357,128 — more than the amount borrowed.

Practical tips

A 15-year term raises the payment but can cut total interest by more than half compared with 30 years.
An extra 5% down payment reduces both the payment and the interest, and may remove mortgage insurance.
Even 0.25% off the rate saves thousands on a 30-year loan — always compare at least three lenders.
Budget 1–2% of the home price per year for maintenance on top of the payment.

Monthly payment per $100,000 borrowed (principal & interest)

Rate	15 years	20 years	30 years
4%	$739.69	$605.98	$477.42
5.5%	$817.08	$687.89	$567.79
6.5%	$871.11	$745.57	$632.07
8%	$955.65	$836.44	$733.76

Common mistakes

1 Budgeting only principal and interest, then being surprised by tax, insurance and fees in the real payment.
2 Putting every spare dollar into the down payment and leaving no emergency fund for repairs.
3 Comparing offers by monthly payment only, ignoring rate, points and closing costs.

Frequently asked questions

How much house can I afford?

A common guideline is that housing costs should stay under 28–30% of gross monthly income. Work backwards: decide the comfortable payment, then test prices and down payments here until the payment matches.

Does the payment include taxes and insurance?

No. This calculator shows principal and interest. Property tax, homeowner insurance and possible mortgage insurance are extra and vary by location.

Is a bigger down payment always better?

It lowers the payment and total interest and can remove insurance requirements, but keep a cash reserve for moving, repairs and emergencies.

How much does 1% of rate matter?

On a $280,000 30-year loan, dropping from 7.5% to 6.5% saves about $190 per month and roughly $68,000 in total interest.