Mortgage Overpayment Calculator 2026

Updated May 2026HMRC 2026/27Free · No signup
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Most lenders allow up to 10% of balance per year penalty-free.
About this calculator

Overpaying your mortgage reduces your outstanding balance faster, which means you pay less interest over the life of the loan and clear the debt sooner.

Most fixed-rate mortgages allow you to overpay up to 10% of the outstanding balance per year without an Early Repayment Charge. Overpaying beyond this limit can trigger penalties — typically 1–5% of the excess.

As a rule of thumb: every £100/month extra on a £200,000 mortgage at 4.5% saves approximately £20,000 in interest and cuts 4 years off the term.

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