Mortgage Calculator

A mortgage payment is not one number. The loan itself is only part of it, and buyers are often surprised when tax, insurance and mortgage insurance turn a comfortable quote into a stretched budget. This calculator adds all of it up in your browser, so you can try different prices and down payments as quickly as you can type.

How to use the mortgage calculator

1. Enter the home price and choose the currency you think in.
2. Set the down payment, either as a percent of the price or as the cash amount you have saved.
3. Enter the interest rate and term. Thirty and fifteen years are the usual choices.
4. Fill in the ongoing costs — property tax, insurance, any HOA dues, and the mortgage insurance rate your lender quoted.
5. Optionally add an extra monthly payment to see how much interest it saves.

Results update as you type, and the schedule below shows every month of the loan.

How the payment is calculated

The loan part uses the standard amortization formula:

Payment = P × i ÷ (1 − (1 + i)^−n)

That gives principal and interest. The other parts are simple division: yearly property tax and insurance are spread over twelve months, HOA dues are already monthly, and mortgage insurance is the yearly rate applied to the loan amount, divided by twelve.

Each month, interest is charged on the balance you still owe, and whatever is left of the payment reduces that balance. Early on, most of the payment is interest. As the balance falls, the interest shrinks and the principal share grows — which is why the chart is so lopsided in the first years.

Worked examples

A 20% down payment. A 400,000 home with 80,000 down leaves a 320,000 loan. At 6.5% over 30 years, principal and interest come to 2,022.62 a month. Property tax at 1.2% of the price adds 400, and insurance of 1,800 a year adds 150, for a total of 2,572.62. Over the full term the interest alone is about 408,000 — more than the loan itself.

A 5% down payment. On the same home, 20,000 down leaves a 380,000 loan, so the payment rises and mortgage insurance appears. At 0.5% a year, that is 158.33 a month. It is charged until the balance reaches 312,000, which is 78% of the original price. With no extra payments that takes about eleven years; adding 500 a month to principal pulls it in to roughly five.

Extra payments. Take the first example and add 300 a month. The mortgage clears years earlier and the interest saved runs into six figures, because every extra payment removes principal that would otherwise be charged interest for decades.

Common mistakes

• Budgeting for principal and interest only. Tax and insurance can add a third to the payment, and in high-tax areas more than that.
• Forgetting that tax and insurance rise. They are re-assessed, so the payment you see today is not fixed for thirty years even on a fixed-rate loan.
• Treating a rate quote as the whole cost. Points, origination fees and closing costs change the true cost of borrowing. Compare the APR your lender discloses, not only the headline rate.
• Assuming mortgage insurance disappears by itself early. Automatic cancellation is based on the scheduled balance, not on what your home is now worth. If prices rose, you may need an appraisal and a written request.
• Spending the whole approval. Being approved for an amount is not the same as that amount being comfortable once maintenance, utilities and repairs are counted.

Glossary

Everything on this page is an estimate for planning, not a loan offer or financial advice. Your lender’s documents are the numbers that count.

Last reviewed: September 23, 2026