Overpay Your Mortgage or Invest? The Numbers Explained

Overpay Your Mortgage or Invest? What the Numbers Say Right Now

If you have spare cash each month, the pressing question is whether to overpay your mortgage or invest that money instead. With rising mortgage rates, this decision has become increasingly critical for many homeowners in the UK.

As of now, the average mortgage rate stands at 5.5%, a significant jump from previous years. This shift means that for many, the cost of borrowing has increased sharply, making the choice between overpaying a mortgage or investing more complex than ever.

The real decision

Overpaying your mortgage effectively gives you a return equal to your mortgage rate, which in this case is 5.5%. This rate acts as your hurdle rate; any investment needs to outperform this to be worthwhile. With the Bank of England reporting a floating rate rise of 4.5 percentage points since the end of 2021, many homeowners are facing higher costs and tighter budgets.

As a result, the decision to overpay or invest hinges on whether your investments can reliably exceed this hurdle rate. If they cannot, overpaying your mortgage becomes the more attractive option, especially in an environment where interest rates are expected to remain elevated for the foreseeable future.

When overpaying wins

Overpaying your mortgage typically wins when your mortgage rate is high, as it provides a certain return equal to the interest saved. According to the Bank of England, nearly half of all mortgages are likely to see payment increases between December 2024 and early 2028. This impending payment shock means that many homeowners will soon face significantly higher monthly outgoings.

In such a scenario, overpaying your mortgage can help mitigate future financial strain. By reducing the principal balance now, you can lessen the impact of these upcoming increases, making your financial situation more manageable in the long run.

Worked example

Consider a borrower with an illustrative mortgage balance of £200,000 at a current mortgage rate of 5.5%. If they have £500 in spare cash each month, they face a choice: overpay their mortgage or invest that money. Over the next five years, the mortgage interest avoided by overpaying would be as follows: £165 in the first year, £660 in the second, £1,485 in the third, £2,640 in the fourth, and £4,125 in the fifth year.

On the other hand, if the same borrower invests that £500 monthly at an assumed return of 7.0% per annum, the investment value would grow significantly. After five years, the investment would be worth £35,796, with year-by-year values of £6,196, £12,841, £19,965, £27,605, and £35,796 respectively.

This comparison illustrates a critical trade-off: while overpaying the mortgage yields a total interest saving of £9,075 over five years, investing could potentially generate a much higher return, assuming the market performs well. The decision ultimately hinges on whether the borrower prioritises immediate savings or long-term investment growth.

When investing wins

Investing can be the better option when your mortgage rate is low, your time horizon is long, and you have a solid emergency fund in place. If your mortgage rate is significantly lower than the potential returns from investments, it makes sense to channel spare cash into the market.

Moreover, if you can tolerate market volatility and have a long-term perspective, investing can yield greater wealth accumulation over time. This is particularly relevant for those who are not facing immediate financial pressures from rising mortgage costs.

Mixed strategy

1. Clear expensive debt first. Prioritise paying off high-interest debts like credit cards before considering mortgage overpayment or investing.
2. Protect cash reserves. Ensure you have sufficient savings for emergencies before committing extra funds to either option.
3. Use overpayments to reduce rate pressure. This can help ease the financial burden if your mortgage rate increases significantly.
4. Invest what remains if your horizon is long enough. If you have a longer time frame, consider investing any surplus funds after addressing immediate financial needs.

This mixed strategy allows for a balanced approach, ensuring that you are not overly exposed to either risk or debt while still working towards financial growth.

Bottom line

In the current climate, with mortgage rates at 5.5%, overpaying your mortgage often emerges as the stronger option for immediate financial relief. The savings from reduced interest payments are tangible and can provide a buffer against future rate increases.

However, if you have a longer investment horizon and can tolerate some risk, investing may yield greater returns. The mistake is to overlook the numbers; run the calculations based on your specific situation to make the most informed choice.