MONEYSAVVYUK · FREE HOUSEHOLD TOOLS
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Last checked: 26 October 2026. Tax year 2026/27 where applicable.
Compare voluntary overpayments with the payment needed for a shorter mortgage term. Use the same rate to see how payment amounts—not the label on the arrangement—change interest and repayment time.
How I would use this result
Start with a recent payslip, bill, statement or written quote. Replace the example amounts, change one assumption at a time, then check whether the difference would affect your household budget. Keep the assumptions beside the result so you can revisit the comparison when circumstances change.
How the calculation works
Calculate repayment-mortgage payments using monthly interest. Compare the existing payment plus your overpayment with the contractual payment for your chosen shorter term. Keep the same rate and stop at the final partial payment.
Example: check the calculation
When the voluntary total payment equals the payment for the shorter term, the modelled interest and payoff time match. There is no automatic flexibility penalty.
Before relying on the result
Repayment mortgages only. Rate held constant throughout; no fees, early-repayment charges, payment recalculations or lender limits. Shortening the contractual term can require affordability checks. Voluntary payments may be more flexible; the tool does not assign a price to that flexibility.
Your questions answered
Does an overpayment always shorten the term?
Not if the lender reduces future payments. Check how your lender applies it.
Are the results a lender quote?
No. Ask your lender about charges and the actual new payment schedule.
Why might both options match?
Identical cash flows at the same rate produce equivalent amortisation.
Sources and checking
Rules checked on 26 October 2026. Tax parameters, where applicable, are for 2026/27. User-entered prices and growth assumptions are not verified market rates.
Related MoneySavvyUK tools
For a practical next step, visit my free workbook and money tools, or browse my household planners. Calculators remain free and do not require an email address.
Created by Dr Kalpana Govindaraasan, the PhD scientist and UK mum behind MoneySavvyUK. I am not a financial adviser. These are planning estimates and general information.
Created by Dr Kalpana Govindaraasan at MoneySavvyUK. General information and planning estimates, not personal financial advice. Report a problem with this calculator.