How big would your ISA need to be to earn £100,000 a year in passive income?

Ben McPoland explores the huge income potential of ISAs and highlights a FTSE 100 stock that has made investors wealthier over the past two years.

| More on:

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.

A rear view of a female in a bright yellow coat walking along the historic street known as The Shambles in York, UK which is a popular tourist destination in this Yorkshire city.

Image source: Getty Images

Most people in the UK don’t earn £100k a year in wages, so to generate that much in tax-free passive income in an ISA might sound like pie in the sky. The sort of reverie one might have on the way to work on a grey, wet morning (we’ve had lots of those recently).

But is it a pipe dream? Here, I want to look at the numbers to see how realistic this is inside a Stocks and Shares ISA.

Trailblazers

Since 2017, the ISA allowance has stood at £20k a year. By maxing this out every year, and the allowances before that, some investors have managed to build seven-figure portfolios.

Indeed, industry data shows there are over 5,000 ISA millionaires, with some portfolios topping £10m!

Naturally, the majority of these investors are older, as it takes time to build that sort of pot. Moreover, people generally don’t start thinking about investing money — rather than simply spending it — until the grey hairs start emerging.

But these trailblazers show what’s possible over the long run. A £1.43m ISA portfolio that yields 7% would throw off roughly £100k in passive income every year (excluding brokerage fees).

In other words, dividend stocks held would pay that much in dribs and drabs throughout the year.

Aiming for £1.43m

Assuming someone can afford to invest half the ISA allowance — £833 a month — it would take roughly 28 years to reach £1.43m. This assumes a 10% average return and that all dividends are reinvested along the way to fuel compounding.

If this investor were able to invest more over time as their career progressed — averaging £15,000 every year, say — this target could be reached in less than 24 years. Generate a 12% return, and the time frame comes down again, to around 21 years.

Of course, stock market returns and dividend yields are never nailed on. So it would be important to build a diversified portfolio to minimise risk, as well as do research before buying shares.

The Motley Fool has plenty of resources for investors just getting started.

A UK starter stock to consider

Investing platform AJ Bell put out interesting data last year about ISA millionaires. It said the top five holdings owned among this group of customers were Shell, Lloyds, Aviva (LSE:AV.), GSK, and BP.

These are all FTSE 100 blue chips that pay dividends. Zooming in on Aviva, this is one I also hold in my portfolio. It’s the UK’s largest home and motor insurance group after its acquisition of Direct Line.

The stock has done really well recently, returning around 43% in the past two years, before dividends.

There are a few reasons why I think Aviva could be worth considering as a starter stock. For one, it’s a trusted brand, with four in 10 UK adults having a policy with the group.

As such, it’s very profitable, with operating earnings per share tipped to grow 11% between 2025 and 2028. It also pays a nice dividend, with the forecast yield at 6.7% (more than double the FTSE 100 average).

Bear in mind, though, that the insurance market is competitive and could see pressure during a recession. But as part of a nice mix of stocks, I rate Aviva moving forward, especially its income growth potential.

Ben McPoland has positions in Aviva Plc. The Motley Fool UK has recommended Aj Bell Plc, GSK, and Lloyds Banking Group Plc. 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

This way, That way, The other way - pointing in different directions
Investing For Beginners

1 FTSE 250 stock I like and 1 I’ll avoid after the stock market correction

Jon Smith analyses the move lower in certain FTSE 250 companies over the past month and picks one that looks…

Read more »

Playful senior couple in aprons dancing and smiling while preparing healthy dinner at home
Investing Articles

Is April 2026 a great time to buy Lloyds shares?

Lloyds shares have been flying over the last two years. And there's one factor that could mean the bank continues…

Read more »

Young mixed-race couple sat on the beach looking out over the sea
Investing Articles

Want to aim for a £500 second income each month? Here’s how much it takes

Christopher Ruane digs into the numbers and mechanics that could let someone with no shares today build an annual second…

Read more »

Aston Martin DBX - rear pic of trunk
Investing Articles

Down 95%, what might it take for the Aston Martin share price to rise 2,000%?

The Aston Martin share price has collapsed. Our writer considers what it might take for it to regain some ground…

Read more »

Investing Articles

How are Diageo shares looking in April 2026?

It's been an eventful year so far, but what has the impact been for Diageo shares, and where might they…

Read more »

UK financial background: share prices and stock graph overlaid on an image of the Union Jack
Investing Articles

P/Es below 7! 3 staggeringly cheap shares despite yesterday’s rally

Investors who fear they have missed their opportunity to buy cheap shares as the stock market recovers might want to…

Read more »

ISA coins
Investing Articles

Want to know what UK investors have been buying in their ISAs?

Looking for stock, trust, and fund ideas this April? Royston Wild discusses what Brits have been stuffing in their Stocks…

Read more »

Mature Caucasian woman sat at a table with coffee and laptop while making notes on paper
Investing Articles

Why aren’t people buying Greggs shares by the bucketload?

Greggs' shares remain in the doldrums. But should Foolish investors consider pouncing while others won't? Paul Summers takes a fresh…

Read more »