Mortgage overpayment calculator

What does paying a little more save?

See the interest saved, the new debt-free date and whether an early-repayment charge changes the answer. Then compare the mortgage's guaranteed saving with cash interest after tax.

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Your mortgage now
Your overpayment
Advanced settingsEarly-repayment charges and the after-tax saving alternative1 active
Early-repayment terms
Saving instead
Interest saved
£47,075

6y 7m cut from the mortgage after the estimated £0 early-repayment charge.

Before and after
Current planWith overpayment
Monthly payment£1,206.22£1,406.22
Time left27 years20y 5m
Interest from today£170,814£123,740
Interest reduction£47,075
What this means
  • Overpaying has the higher guaranteed rateYour mortgage costs 4.75% while savings earn about 3.4% after the tax assumption.
  • Keep accessible cash firstMoney paid into the mortgage is harder to retrieve. Keep a suitable emergency fund before committing spare cash.
  • Inside the stated allowanceThe first-year overpayment stays within the allowance you entered.

Assumes the rate and contractual payment stay constant. Confirm overpayment limits with your lender. Not financial advice.

Method

How this calculation works

Both schedules use standard monthly repayment amortisation. The overpayment schedule applies your lump sum immediately and adds the monthly extra to the contractual payment until the balance reaches zero. ERC exposure compares first-year overpayments with the allowance entered.

Rates and assumptions

Every planning assumption is editable in the calculator.

Full Plainly methodology