How to try and turn an ISA into £20k of passive income a year!

Dr James Fox details how a long-term investing approach using an ISA could be a great way to generate passive income for the future.

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.

Young Black man sat in front of laptop while wearing headphones

Image source: Getty Images

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.

For many of us, passive income is the reason we invest. We may not need the income right now, but we’re building a portfolio that can deliver a healthy revenue stream, when required.

The problem is, many of us just don’t have a portfolio that’s large enough to generate life-changing passive income. In fact, the average net wealth of someone in my age group — 30-34 — is just £14,500.

Even when invested in some of the highest yielding stocks on the FTSE 100, that £14,500 could only generate around £1,200 a year. Clearly, that’s not a life-changing amount of money.

So if I was targeting let’s say £20,000 a year in passive income, how could I do it? Let’s take a closer look.

Step 1

I’ve got to realise it’s going to take time. To generate £20,000 a year in passive income, I’d need £250,000 invested in stocks paying an 8% dividend yield. I’m saying 8% because, right now at least, I believe that’s the highest sustainable yield achievable.

But getting to £250,000 isn’t going to be easy.

Of course, I could throw my money at growth stocks like NIO, Moderna, or CRISPR Therapeutics — all of which have an attractive growth story. But this is risky. The promised growth may not be actualised. Most growth stocks fail.

My choice for investing over the long run is a compound returns strategy. This is essentially investing in dividend stocks, and reinvesting those dividends year after year. The pot grows quicker each year, and benefits if I can commit to regularly investing in it.

So if I invested £14,500 in dividend stocks, and achieve an annualised returns of 10%, after the first year I’ll have £16,000. That doesn’t sound spectacular, but the growth rate increases over time. Nevertheless, it’d still take 28.5 years to turn £14,500 into £250,000.

Step 2

I can expedite the process by investing regularly. This is a great strategy because it allows us to smooth out the peaks and troughs of the market.

So using the above model, when contributing £400 a month and increasing that contribution by 5% annually, it take me just 14.5 years to reach £250,000 as long as my investments perform (which they might not, of course). That’s more like it.

Step 3

Using the above calculation, I’m aiming for a 10% annual return — that’s actually less than the annual returns of the FTSE 250 in recent decades. So by being a savvy investor, and utilising a value-investing strategy, I reckon I can do better than just 10%.

Value investing is a strategy that focuses on stocks that are undervalued and under-appreciated by the market. Warren Buffett, perhaps the most famous of all value investors, tells us to be greedy when others are fearful and fearful when others are greedy.

So for this strategy I’m picking stocks like Lloyds, Barclays and Phoenix Group. All of these offer sizeable dividends — between 5%-9% — and appear significantly undervalued. If I could achieve 12.5% annual returns, it could take me just 12.5 years to reach £250,000.

Step 4

Finally, I’d want to use my ISA because dividends earned in its wrapper are tax-free. I need to appreciate that I can lose money. This is a strong strategy, but nothing is guaranteed in investing.

Please note that tax treatment depends on the individual circumstances of each client and may be subject to change in future. The content in this article is provided for information purposes only. It is not intended to be, neither does it constitute, any form of tax advice. Readers are responsible for carrying out their own due diligence and for obtaining professional advice before making any investment decisions.

Please note that tax treatment depends on the individual circumstances of each client and may be subject to change in future. The content in this article is provided for information purposes only. It is not intended to be, neither does it constitute, any form of tax advice. Readers are responsible for carrying out their own due diligence and for obtaining professional advice before making any investment decisions.

James Fox has positions in Barclays Plc, Lloyds Banking Group Plc and Phoenix Group Holdings Plc. The Motley Fool UK has recommended Barclays Plc 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

Thoughtful man using his phone while riding on a train and looking through the window
Growth Shares

UK interest rates fall again! Here’s why the Barclays share price could struggle

Jon Smith explains why the Bank of England's latest move today could spell trouble for the Barclays share price over…

Read more »

Man hanging in the balance over a log at seaside in Scotland
Investing Articles

2 out-of-favour FTSE 250 stocks set for a potential turnaround in 2026

These famous retail stocks from the FTSE 250 index have crashed in 2025. Here's why 2026 might turn out to…

Read more »

Young female business analyst looking at a graph chart while working from home
Investing Articles

Down over 30% this year, could these 3 UK shares bounce back in 2026?

Christopher Ruane digs into a trio of UK shares that have performed poorly this year in search of possible bargains…

Read more »

Mature people enjoying time together during road trip
Investing Articles

Yields up to 8.5%! Should I buy even more Legal & General, M&G and Phoenix shares?

Harvey Jones is getting a brilliant rate of dividend income from his Phoenix shares, and a surprising amount of capital…

Read more »

Light trails from traffic moving down The Mound in central Edinburgh, Scotland during December
Investing Articles

Up 7.5% in a week but with P/Es below 8! Are JD Sports Fashion and easyJet shares ready to take off?

easyJet shares have laboured in 2025, but suddenly they're flying. The same goes for JD Sports Fashion. Both still look…

Read more »

US Stock

I think this could be the best no-brainer S&P 500 purchase to consider for 2026

Jon Smith reveals a stock from the S&P 500 that he feels has the biggest potential to outperform the index,…

Read more »

Surprised Black girl holding teddy bear toy on Christmas
Investing Articles

Up 20% in a week! Is the Ocado share price set to deliver some thrilling Christmas magic?

It's the most wonderful time of the year for the Ocado share price, and Harvey Jones examines if this signals…

Read more »

Close-up as a woman counts out modern British banknotes.
Investing Articles

I asked ChatGPT for the 3 best UK dividend shares for 2026, and this is what it said…

2025 has been a cracking year for UK dividend shares, and the outlook for 2026 makes me think we could…

Read more »