Overpayment Calculator

    See how regular overpayments could shrink your mortgage term and slash the total interest you pay. Try a few amounts and watch the impact.

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    Mortgage overpayment calculator

    See how overpayments could reduce your mortgage term

    Adjust the figures below to explore how monthly overpayments may affect your mortgage balance, estimated term and total interest paid.

    Monthly overpayment

    £0 per month

    Total monthly payment

    £1,418.43

    Example ways to increase an overpayment

    Important

    This calculator is for illustration only and does not provide financial advice. Results are based on your inputs and assume interest rates and mortgage terms remain unchanged. Actual savings and term reductions may vary. Overpayments may be subject to early repayment charges, so check your mortgage terms before proceeding.

    Term reduction

    —

    Based on your overpayment.

    Interest saved

    £0

    Total interest reduction.

    New term

    35 years

    Current term: 35 years

    Return on overpayment

    £0.00

    Add an overpayment to see your return.

    Visual comparison

    Estimated mortgage balance over time

    • Mortgage with overpayment
    • Mortgage without overpayment

    Talk to an adviser about overpayments
    FAQ

    Overpayment questions, answered

    Common questions about mortgage overpayments, early repayment charges and getting mortgage-free sooner.

    What is a mortgage overpayment?
    A mortgage overpayment is any amount you pay above your normal contractual monthly payment. It can be a regular monthly top-up or a one-off lump sum. Overpayments reduce your outstanding balance faster, which means less interest is charged over the life of the loan and your mortgage can be repaid sooner.
    Will I be charged an Early Repayment Charge (ERC) for overpaying?
    Possibly, so it is essential to check your mortgage contract before making any overpayments. Most lenders allow you to overpay up to 10% of your outstanding balance each year without triggering an ERC, but the exact allowance, the date it resets and the way it is calculated vary by lender and product. If you exceed the allowance, the ERC is usually a percentage of the amount overpaid and can be significant, especially in the early years of a fixed rate. Always confirm your allowance with your lender or adviser before paying anything extra.
    How can I avoid Early Repayment Charges?
    Stay within your lender's annual overpayment allowance, typically 10% of the outstanding balance per year. Check whether the 12-month period runs from the calendar year, the anniversary of your product start date or the anniversary of completion, as this affects when the allowance resets. Spreading larger lump sums across two allowance years, or waiting until you are out of the early repayment charge period, can also help you avoid charges.
    Is it better to overpay monthly or make a lump sum?
    Both reduce your balance and save interest. Regular monthly overpayments build up steadily and are easy to budget for, while a one-off lump sum has an immediate impact on the balance. Use the calculator above to compare the two and see which fits your goals and cash flow best.
    Should I overpay my mortgage or save the money instead?
    It depends on your interest rate, your savings rate and your wider financial picture. If your mortgage rate is higher than the after-tax return on your savings, overpaying often makes sense. However, you should keep an emergency fund, clear higher-interest debts first and consider whether you may need access to that money in future, as overpayments are usually difficult to get back.
    Will overpaying reduce my monthly payment or my term?
    Most lenders keep your monthly payment the same and shorten your term by default, which maximises the interest saving. Some lenders let you choose to reduce your monthly payment instead, keeping the term the same. Check your lender's process so you know which option you are getting.
    Can I overpay during a fixed-rate deal?
    Usually yes, up to your lender's annual overpayment allowance, typically 10% of the balance. Going above that allowance during the fixed period normally triggers an early repayment charge. Once your fixed deal ends and you move onto the lender's standard variable rate or a new product, the rules may change, so always confirm before making larger overpayments.

    Thinking about overpaying?

    Before you make a lump sum or set up regular overpayments, it is worth checking your product terms and how it fits your wider plans. A quick conversation can help you avoid unexpected charges.

    Get in Touch

    Ready to get started with your mortgage?

    Tell us a bit about your plans and we'll be in touch to guide you through your options. We aim to respond within 20 minutes!

    Ves Doctorov

    Ves Doctorov Cert SMP

    Owner & Principal Mortgage Adviser

    07554 663 631ves@themortgageleague.co.uk
    25 Constable Close, Reading, Berkshire, RG5 4US
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