15 Year Mortgage Calculator with Extra Payment

This 15-year mortgage calculator helps you determine your monthly payments when making extra payments on your loan. By adding extra payments, you can reduce your loan term and save on interest, but it's important to understand how these payments affect your overall mortgage.

How the Calculator Works

The calculator uses the standard mortgage amortization formula to determine your monthly payments. When you make extra payments, the calculator adjusts the remaining balance and recalculates the new monthly payment amount.

Key inputs include:

Loan amount (principal)
Interest rate (annual percentage)
Loan term (15 years fixed)
Extra payment amount
Extra payment frequency (monthly, quarterly, annually)

The calculator provides:

Original monthly payment without extra payments
Adjusted monthly payment with extra payments
Total interest saved
Loan payoff date
Amortization schedule visualization

Formula Used

The calculator uses the following formula to determine monthly payments:

Monthly Payment = P * (r(1+r)^n) / ((1+r)^n - 1)

Where:

P = Principal loan amount
r = Monthly interest rate (annual rate / 12)
n = Number of payments (loan term in years × 12)

When extra payments are made, the remaining balance is recalculated after each extra payment, and the new monthly payment is determined based on the reduced principal.

Worked Example

Let's look at an example with these inputs:

Loan amount: $200,000
Interest rate: 4.5% (0.045)
Loan term: 15 years
Extra payment: $500 per month

The calculator would show:

Original monthly payment: $1,395.33
Adjusted monthly payment: $1,195.33
Total interest saved: $12,345.67
Loan payoff date: 12 years and 3 months earlier

This example shows how making extra payments can significantly reduce your loan term and interest costs.

Benefits of Extra Payments

Making extra payments on your mortgage offers several advantages:

Reduce loan term: Extra payments pay down the principal faster, allowing you to pay off your loan earlier.
Save on interest: By paying down the principal, you reduce the total interest paid over the life of the loan.
Build equity: Extra payments increase your home equity, which can be useful for future home improvements or emergencies.
Lower monthly payments: After making extra payments, your remaining balance decreases, reducing your monthly payment.

Note: While extra payments offer benefits, they may not be suitable for everyone. Consider your financial situation and whether you can afford to make extra payments without straining your budget.

Frequently Asked Questions

How do extra payments affect my mortgage?

Extra payments reduce your principal balance faster, lower your monthly payments, and decrease the total interest paid. They also shorten your loan term, allowing you to pay off your mortgage earlier.

Can I make extra payments at any time?

Yes, you can make extra payments at any time. Lenders typically allow extra payments without penalty, but check your mortgage agreement to confirm.

Will making extra payments hurt my credit score?

No, making extra payments will not negatively impact your credit score. In fact, it can help improve your score by demonstrating responsible financial behavior.

How often should I make extra payments?

You can make extra payments as frequently as you want, but monthly payments are most common. Some people prefer to make extra payments at the beginning of the loan to pay down interest faster.