How accurate is the overpayment calculator?

It models your actual mortgage terms — rate, term, and balance — to show interest saved and time cleared early.

Updated 17 September 2026

It models your actual mortgage terms — rate, term, and balance — to show interest saved and time cleared early. It's a projection based on the figures you enter, not a substitute for a lender's official redemption statement. Want to try the same calculation without opening the app? There's a free standalone version at bunse.uk/mortgage-overpayment-calculator.

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