The Quick Answer

It depends on your mortgage rate versus what you would earn elsewhere. If your mortgage rate is higher than your savings rate, overpaying usually makes sense. But there are exceptions worth considering.

The Maths

If your mortgage rate is 4.5% and your savings account pays 4%, overpaying saves you more — because you are effectively earning a guaranteed 4.5% return by reducing your debt. But if you could invest at 6–8% over the long term in a Stocks and Shares ISA, investing might win — with more risk attached.

When Overpaying Makes Sense

  • Your mortgage rate is relatively high (above 4–5%).
  • You have already maximised your ISA allowance for the year.
  • You have a solid emergency fund (3–6 months of essential expenses).
  • You value the certainty of reducing debt over the uncertainty of investment returns.

When It Might Not

  • You have not built an emergency fund yet — that should come first.
  • Your mortgage rate is low (under 3%) and you can earn more elsewhere.
  • You are not maximising your pension tax relief — employer match is free money.
  • You have higher-interest debts (credit cards, personal loans) to clear first.

Overpayment Limits

Most lenders allow you to overpay up to 10% of your outstanding balance per year without early repayment charges. Check your mortgage terms before overpaying — going above the limit can trigger penalties that wipe out the benefit.

The Psychological Factor

Numbers aside, being mortgage-free is powerful. Many people overpay for peace of mind even when the pure maths says invest. There is nothing wrong with that — a financial plan should work for you, not just on a spreadsheet.