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Mortgage Overpayment Calculator FullScreen

Calculate the potential savings and reduction in mortgage term by making additional payments towards your loan. Input your current mortgage details, including interest rate and remaining term, along with the amount and frequency of overpayments.

Mortgage Overpayment Calculator



Details Summary
Without Overpayments With Overpayments

Mortgage Debt Over Time


What is Mortgage Overpayment Calculator

A Mortgage Overpayment Calculator is a tool used to determine the potential savings and reduced mortgage term that can be achieved by making extra payments towards your mortgage. By inputting certain details such as the outstanding loan amount, interest rate, remaining term, and the additional amount you wish to pay, the calculator can provide estimates of the benefits of making overpayments.

Here's how a Mortgage Overpayment Calculator typically works:

  1. Loan Details: Enter information about your current mortgage, including the outstanding loan amount, interest rate, and remaining term.

  2. Overpayment Amount: Specify the additional amount you plan to pay towards your mortgage each month or on an irregular basis (e.g., yearly lump sum payments).

  3. Calculation Results: The calculator will produce various results to demonstrate the impact of overpayments, such as:

    • New Payoff Date: The projected date when your mortgage will be fully repaid based on the increased payments. This can give you an idea of how much time you can shave off your mortgage term.

    • Interest Saved: The estimated amount of interest saved over the course of the mortgage term due to the extra payments. Making additional payments reduces the overall amount of interest that accrues.

    • Monthly Savings: If you've specified a fixed amount for overpayments each month, this figure represents the reduction in your monthly payment once the mortgage is paid off faster.

    • Total Savings: The overall savings achieved by reducing the total interest paid over the life of the mortgage.

Please note that the figures provided by a Mortgage Overpayment Calculator are estimates and should be used for informational purposes only. Mortgage terms may vary, and it's important to check with your lender to confirm any limitations or conditions relating to overpayments and ensure they comply with your mortgage agreement.

How to use Mortgage Overpayment Calculator?

Our Mortgage Overpayment calculator enables you to understand what amount of interest and the amount of time you can save by making a regular overpayment. When you make an overpayment after the loan has commenced, they add to your normal monthly mortgage payment. We look at the effect of making the same overpayment each month with our calculator.

We make it simple to operate. All you need to do is:

  • Put in your mortgage balance as it stands today
  • Input the mortgage interest rate that you are paying
  • Type in the remaining term of the mortgage in years
  • Put in the regular overpayment that you want to make
  • There is also the option to input a currency, but this is not compulsory

Once you have keyed these inputs, press 'Calculate' and the result will appear.

This lets you know the impact of monthly overpayments on your mortgage. It shows you how much time and money you will save. Making an overpayment will reduce the amount of interest you are charged. Our calculator is for demonstration only and should not be relied upon as an absolute figure. It uses certain assumptions and indicates the interest you will save. Some mortgages restrict the amount of cash you can overpay and have early repayment charges, so speak to your lender for details.

Some lenders take your overpayments and use them to reduce your monthly payments rather than your term, so make sure with them before you begin that the overpayments you make will have the desired effect.


The calculator assumes that the interest rate will not change for the entire mortgage term.

The calculator assumes that your monthly overpayments will be the same every month for the rest of the mortgage term.

Our mortgage overpayment calculator uses the standard formula with fixed-rate mortgage loan:

Monthly Mortgage Payment = { Rate / (1 − (1 + Rate) − N) } x Mortgage Amount


N = The Number of Monthly Payments (for a 10 year mortgage loan N = 10 x 12 = 120) ,

Rate (Monthly Interest Rate) = Decimal Rate / 12 , or Rate = (Annual Interest Rate / 100) / 12

You may also be interested in our HELOC Payment Calculator or PITI Mortgage Calculator