Google Mortgage Calculator

Expert Review: This calculator and methodology were reviewed and approved by David Chen, CFA.

Use the Google Mortgage Calculator to quickly estimate your monthly loan payments, total interest costs, and amortization schedule based on the principal amount, interest rate, and term of the loan.

Loan Principal ($):

Annual Interest Rate (%):

Loan Term (Years):

Mortgage Payment Formula

The standard formula used for calculating the monthly payment ($M$) on a fixed-rate, principal and interest loan is as follows:


                    M = P * [ i * (1 + i)^n ] / [ (1 + i)^n - 1 ]
                    

                    Where:
                    

                    P = Principal Loan Amount
                    

                    i = Monthly Interest Rate (Annual Rate / 12 / 100)
                    

                    n = Total Number of Payments (Loan Term in Years * 12)

Formula Source: Investopedia – Amortization | The Balance – Loan Calculation

Variables Explained

Here is an explanation of the variables used in the calculator:

Loan Principal ($): The total amount of money borrowed from the lender.
Annual Interest Rate (%): The yearly interest percentage charged on the loan balance.
Loan Term (Years): The duration over which the loan is scheduled to be repaid.

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What is a Google Mortgage Calculator?

A mortgage calculator, often searched for via ‘Google mortgage calculator’, is a digital tool designed to estimate the cost of a mortgage. By inputting three key variables—the principal amount, the annual interest rate, and the loan term—it rapidly calculates the required monthly payment.

This tool is essential for prospective homeowners and borrowers, as it provides immediate clarity on affordability, allowing users to compare different loan scenarios (e.g., 15-year vs. 30-year terms) and determine the overall financial commitment required for a house purchase.

How to Calculate Monthly Payment (Example)

Let’s use an example to calculate the monthly payment for a loan:

Define Variables: Assume a Principal ($P$) of $300,000, an Annual Rate ($R$) of 5%, and a Term ($T$) of 30 years.
Calculate Monthly Rate ($i$): $i = 0.05 / 12 = 0.0041667$.
Calculate Total Payments ($n$): $n = 30 \times 12 = 360$ payments.
Apply Formula: Plug $P$, $i$, and $n$ into the monthly payment formula: $M = 300,000 \cdot [ 0.0041667 \cdot (1 + 0.0041667)^{360} ] / [ (1 + 0.0041667)^{360} – 1 ]$.
Result: The calculated monthly payment ($M$) is approximately $1,610.46.

Frequently Asked Questions (FAQ)

How does the loan term affect the monthly payment?

A shorter loan term (e.g., 15 years) results in a higher monthly payment but significantly less total interest paid over the life of the loan. A longer term (e.g., 30 years) lowers the monthly payment but substantially increases the total interest paid.

Does this calculation include property taxes or insurance?

No, the calculation provided by this basic calculator only determines the principal and interest (P&I) portion of your payment. It does not include escrows for property taxes, homeowner’s insurance, or mortgage insurance (PMI).

What is the difference between APR and the interest rate?

The interest rate is the cost of borrowing the principal. The Annual Percentage Rate (APR) is a broader measure of the cost, including the interest rate plus certain required fees and costs (like origination fees).

Can I use this to calculate an early payoff?

This calculator is for standard monthly payments. To calculate the impact of extra payments, you would need a full amortization calculator, which is available in our related tools section.

Google Mortgage Calculator