Financial / Mortgage Tools

Mortgage Overpayment Calculator

Compare a standard mortgage result against the same mortgage with a monthly overpayment, so the time and interest difference is clear at a glance.

Mortgage Inputs

Enter your mortgage details and any monthly overpayment you want to test.

Result

Without overpayment

Baseline mortgage result with no extra monthly payment added.

Monthly payment £1,381
Mortgage term 30 years
Total interest £246,983
Result

With overpayment

Mortgage result once the monthly overpayment is included.

Monthly payment £1,631
Mortgage term 21 years 3 months
Total interest £164,999
Difference

Savings

Direct comparison between the baseline and the overpayment scenario.

Extra paid monthly £250
Time saved 8 years 9 months
Interest saved £81,985

How to read the results

  • The first card shows your baseline monthly payment and full mortgage term
  • The second card shows the higher payment once overpayments are included
  • The difference card shows how much sooner the mortgage could end and how much interest could be reduced

Mortgage overpayment calculator FAQ

  • This estimate assumes the mortgage rate stays constant, which may not match a real fixed or variable mortgage product
  • Regular overpayments usually reduce both the remaining term and the total interest paid if your lender applies them to the balance
  • Some lenders limit how much you can overpay each year, so check your mortgage terms before acting on the result

When this page is useful

  • Use it when you already have a mortgage balance and want to compare the standard path against a higher monthly repayment
  • It is most useful for testing whether a fixed monthly overpayment could save enough time or interest to justify the extra cash
  • Use the mortgage payment calculator first if you need to estimate the starting monthly payment for a new property purchase