Overpayment Calculator

What this calculator does

This calculator helps you understand the potential benefits of making overpayments on your mortgage. It shows you how much interest you could save and how much sooner you could be mortgage-free by making either one-off or regular overpayments.

How to use it

1. Enter your current mortgage details (amount, term, type, and interest rate).
2. Enter either a one-off overpayment amount, a recurring overpayment amount (or both).
3. Optionally, compare the benefit of overpaying your mortgage versus putting the same money into a savings account.
4. Click "Calculate" to see your results.

Important notes

• Overpayment limits: Most mortgage lenders limit how much you can overpay each year, typically to 10% of your outstanding balance. Check with your lender for your specific limit.
• Early repayment charges: Some mortgages have early repayment charges if you overpay too much or pay off the mortgage early. This calculator doesn't account for these charges.
• Interest rate changes: This calculator assumes your interest rate remains constant throughout the term of your mortgage. In reality, rates may change, especially if you're on a variable rate or when your fixed-rate period ends.
• Tax on savings: When comparing with savings, the calculator uses the tax rates you select:
  • Basic rate: 20%
  • Higher rate: 40%
  • Additional rate: 45%

Making overpayments

To make overpayments on your mortgage, contact your lender directly. Most lenders allow you to make overpayments online, by phone, or by setting up a standing order. Make sure to specify that the additional payment is an overpayment on your mortgage principal.