If a 40-year-old put £100 a month in a Stocks and Shares ISA, here’s what they could retire on

Ever wonder if you could build a passive income with just £100 a month? Royston Wild examines the wealth-building power of the Stocks and Shares ISA.

| More on:

The content of this article was relevant at the time of publishing. Circumstances change continuously and caution should therefore be exercised when relying upon any content contained within this article.

You’re reading a free article with opinions that may differ from The Motley Fool’s Premium Investing Services. Become a Motley Fool member today to get instant access to our top analyst recommendations, in-depth research, investing resources, and more. Learn More.

Businessman with tablet, waiting at the train station platform

Image source: Getty Images

Unlike a savings account, there’s no a guaranteed return from a Stocks and Shares ISA.

Yet recent history provides a useful guide to what can be achieved with one. According to Moneyfacts, the average investing ISA’s provided a typical annual return of 9.64% since 2015.

This kind of brilliant return would have turned even a modest regular investment into a tasty pile of cash. Indeed, if someone had put £100 into a Stocks and Shares ISA every month over that period they’d have doubled their money (to £20,067).

Want to know how much they could have made by retirement? That’s trickier, but it’s possible to make a rough calculation. Let me show you why.

Here’s your answer

Albert Einstein once called compound interest “the eighth wonder of the world. He who understands it, earns it; he who doesn’t, pays it.

Cool story, I hear you say. What does this have to do with our wealth-creating exercise?

Put simply, time is an investor’s best friend. The longer they have their money in the stock market, the more each pound multiplies into something far bigger.

When figuring out how much £100 a month could become by retirement, then, we need to consider how long that investment is made over.

Let’s say we have a 40-year old just starting their investing journey. Here’s how much they’d have in their ISA by the time they reached 55, 60, 65 and 70, based on the long-term average return:

Retirement ageCash return
55£40,103
60£72,485
65£124,821
70£209,405

Building retirement income

Those are pretty decent returns for just £100 a month, I think. If our investor decided to start drawing down 4% of their portfolio each year at age 70, they’d have a second income of £8,376 on top of the State Pension.

If you’re like me, though, you’ll also look at this and be thinking: could I live off this amount in retirement?

I’m not sure I personally could. This is why being able to increase deposits over time is another essential part of the ISA-building process.

Someone who raised their annual contributions by 5% a year would have £333,540 after 30 years, and a £13,342 non-State Pension income. A 7% rise would give them a £441,294 nest egg, and a £17,651 additional income.

Targeting ISA wealth

None of this is guaranteed, of course. But with a wealth of shares, trusts and funds to choose from, returns like this remain very achievable, in my view.

I personally like the idea of investing in exchange-traded funds (ETFs) like the Xtrackers World Momentum ETF (LSE:XDEM). Indeed, this is a fund I hold in my own portfolio.

By investing in hundreds of global companies (350 in total), it protects returns from turbulence among particular stocks, sectors and regions. This reduces risk and can provide a smooth return over time.

A focus on equities leaves the fund vulnerable to stock market downturns. But then it also allows investors to profit from potential recoveries, generating enormous wealth over the long term.

The Xtracker World Momentum’s 13.6% average return since 2015 illustrates this principle in action. Funds like this can provide a simple and effective way to build a Stocks and Shares ISA for retirement wealth.

Royston Wild has positions in Xtrackers (ie) Public - Xtrackers Msci World Momentum Ucits ETF. The Motley Fool UK has no position in any of the shares mentioned. Views expressed on the companies mentioned in this article are those of the writer and therefore may differ from the official recommendations we make in our subscription services such as Share Advisor, Hidden Winners and Pro. Here at The Motley Fool we believe that considering a diverse range of insights makes us better investors.

More on Investing Articles

DIVIDEND YIELD text written on a notebook with chart
Investing Articles

How big does an ISA need to be to aim for a £1,500 monthly second income?

Harvey Jones shows how building a balanced portfolio of FTSE 100 dividend stocks can produce a high-and-rising second income in…

Read more »

Person holding magnifying glass over important document, reading the small print
Investing Articles

£20,000 invested in BP shares 1 year ago is now worth…

BP shares have rocketed in the past 12 months, yet analysts think the real growth story is only just beginning,…

Read more »

A pastel colored growing graph with rising rocket.
Investing Articles

A 6.8% forecast yield! 1 often-overlooked FTSE 100 income stock to buy today?

This income stock offers a high forecast yield and strengthening momentum, yet many investors overlook it — creating a rare…

Read more »

GSK scientist holding lab syringe
Investing Articles

GSK’s share price is under £22, but with a ‘fair value’ much higher, is it time for me to buy more right now? 

GSK’s share price rose over the last year, but a huge gap remains between its price and fair value —…

Read more »

Businessman hand stacking money coins with virtual percentage icons
Investing Articles

Here’s how investors can aim for £11,363 a year in passive income from £20,000 in this overlooked FTSE media gem

I think this media stock is commonly overlooked by investors looking for high passive income, but it shouldn’t be, given…

Read more »

Tesla car at super charger station
Investing Articles

Why is Tesla stock down 30% since late 2025?

Tesla stock has been a bit of a car crash in 2026. Edward Sheldon looks at what’s going on, and…

Read more »

UK supporters with flag
Investing Articles

Is Wise now the UK stock market’s top growth share?

Wise rose around 4% in the UK stock market yesterday, bringing its four-year gain to 135%. Why are investors warming…

Read more »

Warhammer World gathering
Investing Articles

£20,000 invested in this FTSE 100 stock 10 years ago is now worth this astonishing amount…

This FTSE 100 stock's delivered an amazing return over the past 10 years. James Beard considers whether it’s worth holding…

Read more »