15 Year Fixed Mortage Calculator

Use this 15-year fixed mortgage calculator to estimate your monthly payments, total interest, and loan amortization schedule. A 15-year fixed mortgage offers lower monthly payments compared to a 30-year mortgage, but you'll pay more in total interest over the life of the loan.

How to Use This Calculator

To calculate your 15-year fixed mortgage payments:

Enter the loan amount you're requesting
Input your interest rate (annual percentage rate)
Select the loan term (15 years in this case)
Click "Calculate" to see your monthly payment and other details

The calculator uses the standard mortgage payment formula to determine your monthly payment. You can then compare this with other loan options to make an informed decision.

Formula Explained

The monthly mortgage payment is calculated using the following formula:

Mortgage Payment Formula

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

Where:

M = Monthly payment
P = Principal loan amount
i = Monthly interest rate (annual rate divided by 12)
n = Number of payments (loan term in years × 12)

This formula accounts for the fact that each payment includes both principal and interest, with the interest portion decreasing as the principal balance decreases over time.

Worked Example

Let's calculate a 15-year fixed mortgage for $200,000 at 4.5% annual interest:

Principal (P) = $200,000
Annual interest rate = 4.5% or 0.045
Monthly interest rate (i) = 0.045/12 = 0.00375
Number of payments (n) = 15 × 12 = 180

Plugging these values into the formula:

Calculation Steps

M = 200,000 [ 0.00375(1 + 0.00375)^180 ] / [ (1 + 0.00375)^180 - 1 ]

First calculate (1 + i)^n:

(1.00375)^180 ≈ 4.427

Now calculate the numerator and denominator:

Numerator = 200,000 × 0.00375 × 4.427 ≈ 3,339,000

Denominator = 4.427 - 1 = 3.427

Final monthly payment = 3,339,000 / 3.427 ≈ $974.36

So for this example, the monthly payment would be approximately $974.36, with a total interest payment of about $102,172 over the 15-year term.

Frequently Asked Questions

What is a 15-year fixed mortgage?

A 15-year fixed mortgage is a home loan where the interest rate remains the same for the entire 15-year term. This results in lower monthly payments compared to a 30-year mortgage, but you'll pay more in total interest over the life of the loan.

How does a 15-year mortgage compare to a 30-year mortgage?

15-year mortgages typically have lower monthly payments but higher total interest costs. They're suitable for homeowners who plan to sell or refinance before the term ends. 30-year mortgages have higher monthly payments but lower total interest costs over the loan term.

What factors affect my mortgage payment?

Your mortgage payment is primarily determined by the loan amount, interest rate, and loan term. Other factors that can affect your payment include points (prepaid interest), private mortgage insurance (PMI), and property taxes.

Can I pay extra toward my mortgage?

Yes, paying extra toward your mortgage can help you pay it off faster and save on interest. Many lenders allow biweekly payments (every two weeks instead of monthly) which can save you money over time. You can also consider making lump-sum payments or increasing your regular payments.