Finance template
Mortgage Overpayment Calculator
What an extra amount each month actually buys you — the interest saved and the years knocked off.
- Live formulas
- 95
- Columns
- 8
- File
- 9 KB
$5
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Works in Excel 2013 and later, Microsoft 365, Google Sheets and LibreOffice Calc. Set up to print landscape on one page wide.
About this Mortgage Overpayment Calculator template
Overpaying a mortgage reduces the balance that interest is charged on, which cuts both the total interest and the time left to pay. This Excel mortgage overpayment calculator uses your balance, interest rate, remaining term and monthly overpayment to show exactly what the extra money buys you.
A year-by-year schedule compares your balance with and without overpaying, and the summary shows the months and years saved, the interest saved and how much you save for every £1 overpaid.
Good for
- →Deciding whether to overpay your mortgage or save instead
- →Seeing how much a small monthly overpayment saves over the term
- →Comparing overpayment amounts before changing a standing order
What it works out for you
What overpaying buys you
- →Normal monthly payment
- →You would actually pay
- →Months left at the normal payment
- →Months left when overpaying
- →Months saved
- →Years saved
- →Interest paid without overpaying
- →Interest paid when overpaying
- →Interest saved
- →Extra paid in over the term
- →Saved per £1 overpaid
What you fill in
The table has 8 columns. Calculated columns fill themselves in; the rest are yours to type over.
- →Year
- →Opening balance
- →Paid in year
- →Interest
- →Principal repaid
- →Closing balance
- →Closing without overpaying
- →Ahead by
Settings in the “Loan” box
- →Amount outstanding
- →Annual interest rate
- →Years left to run
- →Extra paid each month
How to use it
Change the four figures in the Loan box and everything re-runs. The last column is the balance you would have had without overpaying, so the gap is the whole point.
The file opens with sample rows so you can see every formula working before you change anything. Type your own figures over them. When you need more rows, insert them inside the existing block rather than underneath it, so the totals keep covering every row.
Shaded, boxed cells below the table are settings the formulas read from. Change those first — every row that depends on them updates at once.
Functions it uses
Every one of these exists in Excel, Google Sheets and LibreOffice, so the file behaves the same wherever you open it.
FVIFERRORMAXMINNPERPMTQuestions about the Mortgage Overpayment Calculator
How does it work out the time saved?
It uses Excel's NPER function to find how many months the mortgage takes with the higher payment, and compares that with the months left on your normal payment.
Does it account for early repayment charges?
No. Many fixed-rate mortgages only allow a set amount of overpayment each year before charges apply, so check your lender's limit first.
Is this financial advice?
No. It shows the effect of overpaying on the figures you enter. Whether overpaying suits you depends on your wider finances.
