How much do I need in a Stocks and Shares ISA to earn a £500 monthly passive income?

A stocks and shares ISA can be a powerful tool for building long-term passive income. But how much capital does it really take to generate £500 a month?

For many investors, the idea of covering a meaningful portion of living costs through investment income is the dream. A £500 monthly stream — or £6,000 a year — could help fund bills, travel, or simply provide greater financial security.

And thanks to the tax advantages of an ISA, every penny of eligible dividends or withdrawals can be kept out of the taxman’s reach.

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.

Dream to reality

Turning that goal into reality requires more than simply picking a handful of dividend-paying companies. The size of the ISA portfolio, the average yield it produces, and the reliability of those income streams all play an important role.

Higher yields may reduce the capital required, but they often come with greater risk. Meanwhile, more conservative income strategies typically demand a larger starting pot.

So what does the maths actually say?

By working through a few realistic yield scenarios, it’s possible to estimate how large a stocks and shares ISA might need to be to deliver that £500 monthly target — and whether the goal looks comfortably achievable or still some way off.

At a 3% yield, an investor would need about £200,000 invested.
At 4%, that falls to roughly £150,000.
At 5%, around £120,000 could do the job.
And at 6%, the target drops to about £100,000.

Higher yields reduce the capital required, but they often come with greater risk and less dependable dividends. For many investors, aiming for a balanced yield with reliable long-term income growth may be the more sustainable approach.

Growth and dividends

Knowing where to invest can be the hard part.

One stock that offers both growth potential and dividends is Arbuthnot (LSE:ARBB).

The stock trades around 8.2 times forward earnings. That’s a big discount to FTSE 100 peers and it’s trading 71% below the average share price target. Admittedly there are only two institutional analysts covering this stock. And because it’s such a small-cap stock, they may not be the most talented of analysts.

Then there’s the dividend. On a forward basis it sits around 6.1%, potentially rising to around 6.6% in FY26. The forecast suggests this will be covered two times by earnings, inferring a level of stability.

Operationally, Arbuthnot appears to be thriving by leveraging its relationship-led model. With a £4.42bn deposit base fueling £2.32bn in customer loans, its liquidity is robust. Diversified growth in specialist lending (£895.9m) and wealth management (£2.38bn) complements its expanding regional footprint, exemplified by the Bristol office’s trajectory toward a £1bn balance sheet.

One risk, however, is the bank’s high sensitivity to interest rate fluctuations, as falling rates can compress net interest margins when deposit costs reprice more slowly than loan yields.

Nonetheless, I certainly believe it’s worth considering.

The post How much do I need in a Stocks and Shares ISA to earn a £500 monthly passive income? appeared first on The Motley Fool UK.

More reading

• UK shares: a once-in-a-decade chance to grow rich?
• Move over FTSE 100 banks, there’s value in smaller lenders
• I asked ChatGPT for the best income stocks to buy in 2026 and here’s what it said…

James Fox has positions in Arbuthnot Banking Group Plc. 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.

See author's posts