Mortgage Overpayment Calculator
See how much you could save by making extra mortgage payments
Last updated: August 2026
Current Mortgage
Overpayments
Annual: £2,400
Optional large payment now
Typical: 10% of balance per year
Total Interest Saved
£36,280
By making regular overpayments
Time Saved
6.1 years
73 months
Comparison
Without Overpayments
With Overpayments
Balance Over Time
Interest Breakdown
Overpayment Benefits
- • Save £36,280 in interest charges
- • Become mortgage-free 6.1 years earlier
- • Reduce monthly payment by remortgaging at lower balance
- • Build equity faster for future flexibility
- • Guaranteed return equal to your mortgage rate (4.5%)
Understanding Mortgage Overpayments
The Power of Overpaying
Every extra pound you pay goes directly toward reducing your mortgage balance, not interest. This reduces the amount of interest you pay over the mortgage term and can save you thousands.
Example:
£200,000 mortgage at 4.5% over 25 years: Standard cost = £111,100 in interest. Overpay £200/month and save £36,280while finishing 6.1 years early.
Calculator shows potential savings based on consistent overpayments. Always check your mortgage terms before overpaying.
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Reviewed by
Alexandre Bernier, LLM (UK), CFP®, CIM®, PFP®. Financial planner with 18 years in banking and wealth management, holding a UK master of laws and the Canadian CFP®, CIM® and PFP® designations. Writes and reviews every calculator and article on FinanceToolz.
Last updated: August 2026. How figures are sourced, reviewed and corrected is set out in our editorial policy. This is general information, not regulated financial advice.
Sources
Every rate and threshold used by this calculator is taken from the official pages below. If a figure here disagrees with one of these, the official page is right, please tell us.