Mortgage Calculator

Drag the sliders to set the home price, your down payment and the rate. The console updates the full monthly payment (PITI), lifetime interest, the principal-vs-interest chart, and a month-by-month payoff table.

How the payment is calculated

Principal and interest use the standard amortized-loan formula:M = P · r · (1+r)^n / ((1+r)^n − 1), where P is the loan amount, r is the monthly rate (APR ÷ 12), and n is the number of monthly payments. On top of that go the monthly property tax and homeowners insurance, any HOA dues, and — while your loan is more than 80% of the home's value — an estimated 0.5%/year of PMI. Together lenders call this PITI.

Worked example

A $450,000 home with $90,000 down (20%, so no PMI) at 6.85% over 30 years: the loan is $360,000, and principal & interest work out to about $2,359/month. Add $375 for property tax and $150 for insurance and the full payment is roughly $2,884/month. Over the life of the loan you pay about $489,000 in interest — more than the amount borrowed.

Where each dollar goes

Early payments are almost all interest; the crossover — where more of each payment goes to principal than to interest — comes surprisingly late on a 30-year loan. The chart above shows the split year by year. This is why an extra $200/month from the start pays the loan off around 5 years early — see how amortization works.

PMI, and how to drop it

With less than 20% down you'll usually pay private mortgage insurance. By federal law it must be cancelled automatically once the balance reaches 78% of the original price, and you can request it at 80% — sooner if you've made extra payments or the home has appreciated. See PMI explained.

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Frequently asked questions

What is included in the monthly payment?

Principal and interest on the loan, plus one-twelfth of your annual property tax and homeowners insurance, any HOA dues, and PMI while your loan-to-value is above 80%. Lenders call this bundle PITI.

When do I pay PMI?

Private mortgage insurance is usually required when your down payment is under 20% of the price. It typically drops off automatically once the loan balance reaches 78% of the original value. This calculator applies an estimated 0.5% annual PMI while LTV is above 80%.

How is the amortization schedule built?

Each month, interest is charged on the remaining balance and the rest of your payment reduces the principal. Early on, most of the payment is interest; near the end, almost all of it is principal.

Should I choose a 15- or 30-year term?

A 15-year loan has a higher monthly payment but a lower rate and far less total interest. A 30-year loan is more affordable month to month but costs much more over its life. Try both here and compare the total interest.

How much house can I afford?

A common guideline is that your total monthly housing payment (PITI) should stay under about 28% of gross monthly income, and all debt payments under about 36%. A safer real-world target is a housing payment near 25% of take-home pay. Model a payment you're comfortable with and work back to a price.

What does making one extra payment a year do?

On a 30-year loan it typically cuts the term by about 4 to 5 years and saves tens of thousands in interest, because every extra dollar goes straight to principal and stops accruing interest for the rest of the loan. Extra payments made early save far more than the same amount later.

Are property taxes and insurance really part of the payment?

If you have an escrow account — most borrowers with less than 20% down do — the lender collects one-twelfth of your annual property tax and homeowners insurance with each payment and pays those bills for you. That's why the monthly figure (PITI) is well above principal and interest alone.

Does a lower interest rate always mean a lower total cost?

Not if you pay points to get it, or extend the term. Paying $6,000 in discount points to shave 0.25% off the rate only pays off if you keep the loan long enough for the monthly saving to add up. Compare APR and total interest, not just the headline rate.

Last reviewed: September 2026. Figures and formulas are checked against their published sources; see the site's data notes.