Mortgage vs pension: what the numbers mean for your finances
To bring the decision to life, the analysis looks at an individual with:
- a £200,000 mortgage over 20 years at 4% interest
- a £10,000 bonus each year for five years
We compare two approaches:
- Using each bonus to overpay the mortgage
- Paying each bonus into a pension, assuming a 7% net annual return – the return, after fees. Please note that this is just an example and not a guaranteed return. Your actual returns may be lower or higher.
Under both options, the mortgage is eventually cleared. But over the longer term, the pension‑first approach consistently produces a higher total level of wealth – even after taking the cost of mortgage interest into account.
To understand this, we need to distinguish between tax bands – the 40% band, the 45% band, and so on – and the ‘effective marginal rate’. This is the combined tax and loss of benefits and allowance, on the top slice of your income – the bit for which the effective marginal rate is the highest.
For a 40% taxpayer, paying bonuses into a pension rather than towards the mortgage could result in around £57,000 more in pension savings after 20 years. For taxpayers with an effective marginal rate that goes beyond this, the savings are even higher, underlining just how valuable higher‑rate tax relief can be when combined with long‑term compounding (where the interest on your initial investment keeps growing over time).
Its important to remember that money paid into a pension is generally not accessible until at least age 55 (rising to 57 from April 2028). This is an important factor to consider when deciding how to use a bonus.
Capturing higher tax relief through pension contributions
One of the most striking findings relates to people whose tax rate changes over time.
Some individuals face an effective marginal tax rate of 60% due to the tapering of the Personal Allowance once income exceeds £100,000. If their income later rises – for example, when changing roles, or having been promoted – they may move into a 45% tax band.
In these cases, the opportunity to contribute to a pension while in the 60% band can be extremely valuable. According to the analysis, someone paying an effective marginal rate of 60% tax today but only 45% tax in the future when drawing income (marginal tax rate) could be almost £86,000 better off after 20 years by choosing pension contributions over mortgage overpayments.
This is a clear example of how timing and tax planning can make a significant difference to long‑term outcomes.
How pension contributions can help families regain valuable childcare benefits
For households with young children, the potential advantages can be even greater.
Parents earning above £100,000 begin to lose access to:
- Tax‑free childcare
- 30 funded hours of nursery care
Both are worth thousands of pounds each year. A pension contribution that brings taxable income back below £100,000 can restore access to these benefits, while also attracting pension tax relief.
This interaction between pension contributions and family entitlements is often overlooked – yet it can be one of the most effective ways to improve a household’s financial position.
How basic‑rate taxpayers can benefit from prioritising pension contributions
The pension‑first approach isn’t only beneficial for higher earners.
A basic‑rate taxpayer who expects their income to rise into the higher rate band in future may also benefit from prioritising pension contributions due to compounding growth over time. The benefit is lower, as less tax relief is received at outset, but the analysis shows that they could be around £23,000 better off over 20 years, compared with overpaying the mortgage.
Do lower investment returns change the case for pension contributions?
The main comparison assumes a 7% net annual return. But what if returns are more modest?
Even at a 5% net return, the pension‑first approach remains attractive for many people. Higher‑rate taxpayers could still be around £16,000 better off after 20 years. However, the value of pension investments can go down as well as up and you could get back less than you invested.
For individuals currently in the 60% marginal tax band who expect to move into the 45% band later on, the effect is even more pronounced – with potential gains of around £43,000.
However, pensions don’t always come out on top. For people moving from basic‑rate tax today into higher‑rate tax later, mortgage overpayments could deliver a better outcome. They could be around £16,500 better off in the analysis.
The right answer often depends on your own tax journey and financial goals. This highlights an important point: when thinking about long‑term planning, it’s useful to consider not only your tax position today, but how it may change as your career develops.
Mortgage‑free or pension‑rich? How to find the right financial balance
For many people, becoming mortgage‑free is a major personal milestone. It can bring confidence and a sense of security. As Ed Wood, Senior Financial Planner at Rathbones, notes:
“There’s no single right answer when it comes to choosing between overpaying the mortgage and saving into a pension. Both can strengthen your long‑term financial position, and the right choice will depend on your goals, your mortgage rate, your tax position and your attitude to risk.”
A key message from the analysis is that the decision doesn’t have to be all or nothing. Many households may benefit from a balanced approach – making regular mortgage overpayments while also paying part of a bonus into a pension. This can help reduce interest costs today, while building long‑term retirement wealth for the future.
How to make the most of your bonus season at the end of the tax year
As the end of the tax year approaches, bonuses offer a valuable opportunity to support long‑term financial goals. For many people – particularly higher earners – pension contributions can be a highly effective use of that extra income, thanks to the combination of tax relief, investment growth and potential family benefits. But the best choice depends on your own circumstances: your mortgage terms, your tax position, how your income may change, your long‑term priorities and changing legislation.
A financial planner can help you weigh up your options and choose the approach that supports your goals with confidence. Please reach out to your usual Rathbones contact or fill out our enquiry form below to get in touch. We’re here to help.
