Adding Money to Mortgage Calculator

Adding extra money to your mortgage can significantly reduce your payoff date and save on interest costs. This calculator helps you determine exactly how much you'll save by making extra payments, whether you're adding to your regular payments or making lump-sum payments.

How Adding Money to Your Mortgage Works

When you add money to your mortgage, you're essentially making extra principal payments. This reduces the principal balance of your loan faster, which means you'll pay less interest over the life of the loan. There are two main ways to add money to your mortgage:

Extra Regular Payments

Adding a fixed amount to each of your regular mortgage payments. For example, if your regular payment is $1,500 and you add $200, your new payment will be $1,700.

Lump-Sum Payments

Making one-time large payments to your mortgage. This can be especially effective if you receive a tax refund, inheritance, or bonus.

Note: Adding money to your mortgage doesn't affect your interest rate. It only changes how quickly you pay off the principal balance.

Benefits of Adding Money to Your Mortgage

Faster payoff of your mortgage
Reduced interest costs over the life of the loan
Potential tax benefits if you itemize deductions
Freedom from mortgage payments sooner

Potential Downsides

May not be feasible if you're already at your budget limit
Could affect your credit score if you make payments irregular
May not be the best option if you're planning to sell soon

How the Calculation Works

The calculator uses the following formulas to determine your mortgage payoff date and interest savings:

Mortgage Payment Formula

P = L × [r(1 + r)^n] / [(1 + r)^n - 1]

Where:

P = Monthly payment
L = Loan amount
r = Monthly interest rate (annual rate ÷ 12 ÷ 100)
n = Number of payments (loan term in years × 12)

Payoff Date Calculation

The calculator simulates your mortgage payments month by month, applying your regular payments plus any extra payments you specify. It tracks the principal balance each month until it reaches zero.

Interest Savings Calculation

Total interest paid with extra payments = Total interest paid without extra payments - Interest saved by adding money

The calculator assumes you make all payments on time and that your interest rate remains constant throughout the life of the loan.

Worked Examples

Example 1: Extra Regular Payments

You have a $200,000 mortgage at 4% interest for 30 years. Your regular monthly payment is $1,199.64. If you add $200 to each payment:

New monthly payment: $1,399.64
Original payoff date: December 2045
New payoff date: October 2038
Interest saved: $32,500

Example 2: Lump-Sum Payment

Same mortgage as above. You make a one-time payment of $20,000 at the end of the first year:

Principal after first year: $188,000
New payoff date: December 2044
Interest saved: $1,500

Tip: The impact of extra payments is most significant in the early years of your mortgage. Adding money later in the loan term will have a smaller effect on your payoff date.

Frequently Asked Questions

How much can I save by adding money to my mortgage?: The exact amount you'll save depends on your loan amount, interest rate, loan term, and how much extra you're adding. Use the calculator to get precise numbers for your situation.
Is it better to add money to my mortgage or refinance?: Adding money to your mortgage is typically less expensive than refinancing, especially if you have good credit. However, refinancing may offer a lower interest rate if market rates have dropped.
Can I add money to my mortgage if I'm behind on payments?: If you're behind on payments, you should contact your lender first. They may have special programs for current mortgage holders. Adding money to your mortgage while behind may not be the best option.
Will adding money to my mortgage affect my credit score?: Making extra payments to your mortgage can actually improve your credit score by reducing your credit utilization ratio and showing lenders you're managing your debt responsibly.
Should I add money to my mortgage if I'm planning to sell soon?: If you're planning to sell your home within 5 years, it may not be worth adding money to your mortgage. The interest savings may not offset the cost of refinancing when you sell.