We have some exciting news to share! The Motley Fool UK has now become The Twelfth Magpie -- an independent, UK-owned company, led by our long-serving UK management team — Mark Rogers, Chris Nials and Heather Adlington. In practical terms, it’s the same team you know, now fully focused on serving our UK readers and members.

Just as importantly, our approach remains unchanged: long-term, jargon-free, and on your side. This site is our new home, and there will be extra tweaks made across the coming few days as we settle in. So if anything looks a little off, please bear with us!

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.

How much do you need in an ISA to target a £513.75 monthly passive income?

Our writer reckons a Stocks and Shares ISA is a great way of building a second income. But what an investor does with the dividends is key.  

| More on:
Passive and Active: text from letters of the wooden alphabet on a green chalk board

Image source: Getty Images

You’re reading a free article with opinions that may differ from The Twelfth Magpie’s Premium Investing Services. Become a member today to get instant access to our top analyst recommendations, in-depth research, investing resources, and more. Learn more, and get a free 'Best Buy Now' stock!.

Whenever I think of ISAs, ABBA’s hit Money, Money, Money comes to mind. The opening lyrics are: “I work all night, I work all day to pay the bills I have to pay. Ain’t it sad?”

Yes, it is.

Should you buy Standard Life shares today?

Before you decide, please take a moment to review this report first. Despite ongoing uncertainties from US tariffs to global conflicts, Mark Rogers and his team believe many UK shares still trade at substantial discounts, offering savvy investors plenty of potential opportunities to learn about.

That’s why this could be an ideal time to secure this valuable research – Mark’s analysts have scoured the markets to reveal 5 of his favourite long-term ‘Buys’. Please, don’t make any big decisions before seeing them.

That’s why, many years ago, I decided to set aside some of my disposable income and started investing in the stock market. I opened an ISA to supplement my salary with dividends.

According to MoneySuperMarket, the average person has £513.75 a month left over after paying essential bills. But how much would be needed in an ISA to earn the same amount from dividends? Let’s see.

A bit of number crunching

The answer to this question depends on the level of return achieved.

For example, the FTSE 100’s currently (9 January) offering a yield of 3.2%. The average for the 10 biggest (by market cap) companies on the index is 3.5%. Better still, an equal investment in each of the five highest-yielding Footsie stocks would return 7.1%. These figures are based on dividends paid over the past 12 months, although there can be no guarantee that history will be repeated when it comes to shareholder returns.

Under these three scenarios, an ISA would need to be worth £192,656, £176,143, and £86,831 respectively, to generate a disposable income equal to the UK average.

Admittedly, these are large sums. Although, I reckon it’s possible to get close to them by saving as much as possible over an extended period.

According to AJ Bell, from January 1984 to December 2024, the FTSE 100 achieved an annual return of 5.2%. An individual investing £250 a month for 25 years at this rate, would build an ISA worth £154,065.

An alternative approach

However, if dividends had been reinvested – a process known as compounding – it would have been possible to do better. From January 1986 to December 2024, the average annual total return of the index was 8.6%. At this level, a monthly investment of £250 would grow to £264,180 after two and a half decades.   

That’s why, as tempting as it might be to bank the dividends and pay those bills that ABBA sang about in the 1970s, it’s better — if individual circumstances allow — to reinvest them.

One possible option

For someone looking to follow a similar strategy, with its current yield of 7.4%, I reckon Phoenix Group Holdings (LSE:PHNX) is a dividend share to consider. It looks as though it’s going to raise its payout in 2025. If it does, it will mark a decade of increases.

Over the long term, the savings and retirement group’s likely to benefit from an ageing population and an expected increase in the state retirement age. However, it does have to contend with competition from some lower-cost challengers. Also, with nearly £290m of financial assets on its balance sheet, the group remains vulnerable to global market volatility.

However, its results for the six months ended 30 June 2025, were encouraging. Compared to a year earlier, they showed a 20% increased in adjusted operating profit, a 9% rise in operation cash generation, and a 3% improvement in its Solvency II ratio.

That’s why I think Phoenix Group is an excellent passive income stock to consider including in a well-diversified portfolio of shares.

James Beard has no position in any of the shares mentioned. The Motley Fool UK has recommended Aj Bell 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

Middle-aged white man pulling an aggrieved face while looking at a screen
Investing Articles

This FTSE share’s crashed 31%, and I’ve just bought it. Have I gone crazy?

Sage shares have crashed as worries over AI disruption have grown. Royston Wild reveals why this could be a top…

Read more »

piggy bank, searching with binoculars
Investing Articles

8%-yielding Legal & General shares just gave me another 395 reasons to like them

Harvey Jones is thrilled by the high rate of income he's getting from Legal & General shares, but he'd be…

Read more »

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

Could I REALLY retire on a Stocks and Shares ISA with passive income shares?

Looking to make an extra cash stream in later life? Royston Wild explains how passive income shares could help him…

Read more »

Young Caucasian man making doubtful face at camera
Dividend Shares

I suspect this will trigger a stock market crash!

After three years of double-digit returns, I fear a US stock market crash looks increasingly likely. But might I shelter…

Read more »

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

How to buy growth stocks at below-market prices

Don’t want to pay market prices for growth stocks? Here's a sneaky strategy investors can use to get deals at…

Read more »

CEO Mark Zuckerberg at F8 2019 event
Investing Articles

Are Meta shares at the start of a comeback?

Shares in Meta Platforms have been held back by the firm’s high-risk approach to AI. But is this the moment…

Read more »

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

With dividend yields averaging above 7%, are these 2 UK shares worth considering?

Muhammad Cheema looks at two UK shares: ITV and Legal & General. With yields of 6.1% and 8.1%, should investors…

Read more »

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

How much do you need to invest in dividend stocks to be able to retire?

Some 77% of people in the UK won't have enough income to manage a moderate retirement. Here’s how dividend stocks…

Read more »