Mortgage Overpayment Calculator

Regular overpayments go straight to capital — small amounts shave years off the term. Most lenders allow 10%/yr overpayment penalty-free on fixed deals.

Result

New payoff time17y 3m (was 22y)
Term cut by57 months
Interest saved£26,702.02
Monthly payment incl. overpay£1,394.77
New effective LTV-free balance£200,000.00

How it's calculated

  1. 1

    Baseline payment on £200,000.00 @ 4.5% for 22y = £1,194.77/mo

  2. 2

    Overpayments go 100% to capital — they skip all future interest on that principal

  3. 3

    Simulation applies £200.00/mo overpay month-by-month until balance hits zero

Mortgage Overpayment Calculator — FAQs

Is overpaying worth it?

At 4.5% mortgage rate, every £1 overpaid saves ~£1–2 in future interest — equivalent to a tax-free 4.5% return if your savings rate is lower.

Lump sum or monthly overpayment?

Monthly wins if you'd otherwise spend the money; a lump starts saving interest immediately — either beats the minimum payment.

Penalty-free limit?

Most UK fixed deals allow ~10% of the balance per year overpayment without early repayment charge — check your mortgage terms first.

Related calculators

Loan-to-Value CalculatorLTV CalculatorRemortgage LTV CalculatorMortgage LTV CalculatorHome Equity CalculatorEquity CalculatorHELOC CalculatorStamp Duty Calculator UKUK Stamp Duty CalculatorSecond Home Stamp Duty CalculatorCommercial Stamp Duty CalculatorRental Yield CalculatorRental Yield CalculatorBuy-to-Let Mortgage CalculatorSDLT Calculator

Need a Custom Tool Built?

We build calculators, estimators and internal tools for businesses in the UK and North America.

Get a Quote

Embed this Mortgage Overpayment Calculator on your site

Free to use — paste this snippet into any webpage. It auto-resizes and includes a small attribution link. Add ?theme=dark to the iframe URL for dark mode.

Need help? See the embed guide for WordPress, Webflow, Squarespace & more.