How is a monthly mortgage payment calculated?

The principal and interest portion uses the amortization formula M = P[r(1+r)^n] / [(1+r)^n - 1], where P is the loan amount, r is the monthly interest rate (annual rate divided by 12), and n is the total number of monthly payments. Property tax and home insurance are added on top to get the full monthly cost.

What is included in PITI?

PITI stands for principal, interest, taxes, and insurance. Principal and interest come from the amortization formula. Property tax is a percentage of the home value charged annually, divided by 12. Home insurance is an annual premium divided by 12.

How does the down payment affect my monthly payment?

A larger down payment reduces the loan amount, which directly reduces the monthly principal and interest. It can also help avoid private mortgage insurance and may qualify you for a lower interest rate. Experiment with different down payment percentages to see the impact.

Is my financial information sent to a server?

All calculations run locally in your browser using JavaScript. No values you enter are sent to any server.

Monthly Mortgage Payment Calculator

Estimate your monthly mortgage payment from loan amount, down payment, interest rate, and term. The calculator uses the standard amortization formula and adds optional property tax and home insurance. All math runs locally in your browser.

Currency

Home price

Down payment

Interest rate (% per year)

Term (years)

Property tax (% per year, optional)

Home insurance ($ per year, optional)

Formula: M = P[r(1+r)^n] / [(1+r)^n - 1], where P = loan amount, r = monthly rate, n = months

How it works

The principal and interest portion of your payment is computed with the standard amortization formula M = P[r(1+r)^n] / [(1+r)^n - 1], where P is the loan amount after subtracting your down payment, r is the annual interest rate divided by 12, and n is the term length multiplied by 12. Property tax and insurance entries are converted to monthly amounts and added on top to produce the full PITI figure, so changing any input recomputes the total instantly.

Processing runs in your browser

Every calculation runs locally in your browser as JavaScript. No loan amounts, interest rates, or amortization details leave your device at any point. You can check this yourselfin your browser's DevTools Network tab.

Calculations are estimates for informational purposes only. Consult a financial professional for advice.

Frequently asked questions

How is a monthly mortgage payment calculated?: The principal and interest portion uses the amortization formula M = P[r(1+r)^n] / [(1+r)^n - 1], where P is the loan amount, r is the monthly interest rate (annual rate divided by 12), and n is the total number of monthly payments. Property tax and home insurance are added on top to get the full monthly cost.
What is included in PITI?: PITI stands for principal, interest, taxes, and insurance. Principal and interest come from the amortization formula. Property tax is a percentage of the home value charged annually, divided by 12. Home insurance is an annual premium divided by 12.
How does the down payment affect my monthly payment?: A larger down payment reduces the loan amount, which directly reduces the monthly principal and interest. It can also help avoid private mortgage insurance and may qualify you for a lower interest rate. Experiment with different down payment percentages to see the impact.
Is my financial information sent to a server?: All calculations run locally in your browser using JavaScript. No values you enter are sent to any server.

Monthly Mortgage Payment Calculator

How it works

Processing runs in your browser

Frequently asked questions

Related tools