Mortgage Calculator

Enter a home price, down payment, interest rate and term — then add property tax and insurance — to see your full monthly payment and the interest you’ll pay over the life of the loan.

Your mortgage
Monthly payment
—
Principal & interest
Property tax
Home insurance
Loan summary
Down payment
Loan amount
Total interest
Enter the home price, down payment, rate and term to estimate the monthly payment.

Every calculation runs in your browser — the figures you enter never leave your device.

FAQ

How is the monthly payment worked out?

The loan amount — the home price minus your down payment — is spread across the term with the standard amortization formula, so a fixed principal-and-interest amount clears it by the end. A monthly share of your yearly property tax and home insurance is then added on top to give the full payment.

What does the monthly payment include?

Principal and interest on the loan, plus one twelfth of the yearly property tax and one twelfth of the yearly home insurance. The total interest shown covers only the loan itself — tax and insurance are ongoing costs, not interest.

How do I enter property tax and insurance?

Property tax is a yearly percentage of the home price, since it scales with the property; home insurance is a flat yearly amount. Both are editable estimates that change over time, so use your own figures — or set them to zero to see principal and interest alone.

Does it include mortgage insurance, fees or closing costs?

No — it covers principal, interest, property tax and home insurance. Mortgage insurance, lender fees, closing costs and any future rate or tax changes aren’t modelled, and what a lender requires varies by country. Treat it as a way to compare scenarios, not a loan quote.

Written and reviewed by the BroBroGo editorial team.Last updated:

Calculating Monthly Mortgage Payments and Total Interest

A mortgage payment is composed of several distinct financial elements. To estimate a monthly payment, the calculation requires the home price, the down payment, the annual interest rate, and the loan term in years.

The core of the calculation relies on the loan amount, which is the home price minus the down payment. This principal amount is spread across the selected term using a standard amortization formula to establish a fixed monthly principal-and-interest payment.

To provide a more complete picture of monthly housing costs, the calculation can also incorporate yearly property tax and yearly home insurance. These yearly expenses are divided by 12 and added directly to the monthly principal and interest figure.

Input Parameters and Validation Rules

The calculator processes six primary inputs to generate the payment breakdown:

  • Home price: A numerical value representing the purchase price of the property.
  • Down payment: A numerical value, which can also be entered as a percentage of the home price. This value cannot exceed 100%. If a down payment of 120% is entered, the tool displays the error message "The down payment can’t be more than 100%." and the outputs are shown as —.
  • Annual interest rate: A numerical value representing the yearly interest rate charged by the lender.
  • Loan term: A whole number of years restricted to a range from 1 to 50.
  • Yearly property tax: A numerical value representing the annual tax assessed on the property. If left blank, it is treated as zero.
  • Yearly home insurance: A numerical value representing the annual cost of insuring the home. If left blank, it is treated as zero.

All calculations occur in real-time as inputs are modified. If required fields are cleared, the tool returns to a hint state displaying "Enter the home price, down payment, rate and term to estimate the monthly payment.".

Negative values are not permitted; entering them triggers the error message "These values can’t be negative.". If invalid characters or numbers are entered, the tool displays "Enter valid numbers to calculate.". For inputs that exceed reasonable computational limits, the error message "Those numbers are too large to calculate." is shown.

Understanding the Output Breakdown

Once valid inputs are entered, the tool displays several key outputs, each accompanied by a "Click to copy" hint for easy saving:

  • Monthly payment: The total estimated monthly cost, combining principal, interest, property tax, and home insurance.
  • Principal & interest: The specific portion of the monthly payment dedicated to paying down the loan principal and covering interest charges.
  • Property tax: The monthly share of the yearly property tax (yearly property tax divided by 12).
  • Home insurance: The monthly share of the yearly home insurance (yearly home insurance divided by 12).
  • Down payment: The absolute currency amount calculated from the down payment percentage or numerical input.
  • Loan amount: The total size of the loan (Home price − Down payment).
  • Total interest: The cumulative interest paid over the entire life of the loan.

When active, the tool displays the status message "Estimated over a {n}-year mortgage — for reference only." where {n} represents the entered loan term.

Amortization, Taxes, and Insurance in Housing Budgets

The principal and interest portion of a mortgage is calculated using a fixed amortization schedule, meaning the combined payment remains constant each month, though the proportion going toward interest decreases over time as the principal balance shrinks.

Property tax and home insurance are handled differently. Property tax is treated as a yearly percentage of the home price, as tax assessments typically scale with property value. Home insurance is treated as a flat yearly amount.

It is important to distinguish between these ongoing costs and the loan itself. The Total interest output covers only the interest accrued on the loan principal; property taxes and home insurance are ongoing housing expenses and are not factored into the total interest calculation.

Limitations of Mortgage Calculators

While this tool helps estimate monthly housing expenses, it does not model all potential costs associated with homeownership. The calculator does not include:

  • Private mortgage insurance (PMI) or lender's mortgage insurance (LMI)
  • Lender fees or origination charges
  • Closing costs, escrow fees, or local transfer taxes

Because actual lender rates, property tax assessments, and insurance premiums change over time, these calculations should be used for initial planning and scenario comparison rather than as an official loan quote.

Local Processing and Privacy

Every calculation runs locally in your browser. The figures you enter are processed on your own device and are never uploaded or transmitted to any external servers, ensuring your financial planning data remains private.

Frequently Asked Questions

How is the monthly payment worked out?
The loan amount — the home price minus your down payment — is spread across the term with the standard amortization formula, so a fixed principal-and-interest amount clears it by the end. A monthly share of your yearly property tax and home insurance is then added on top to give the full payment.

What does the monthly payment include?
Principal and interest on the loan, plus one twelfth of the yearly property tax and one twelfth of the yearly home insurance. The total interest shown covers only the loan itself — tax and insurance are ongoing costs, not interest.

How do I enter property tax and insurance?
Property tax is a yearly percentage of the home price, since it scales with the property; home insurance is a flat yearly amount. Both are editable estimates that change over time, so use your own figures — or set them to zero to see principal and interest alone.

Does it include mortgage insurance, fees or closing costs?
No — it covers principal, interest, property tax and home insurance. Mortgage insurance, lender fees, closing costs and any future rate or tax changes aren’t modelled, and what a lender requires varies by country. Treat it as a way to compare scenarios, not a loan quote.

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