Share your opinion and earn yourself a free Motley Fool premium report!

We are looking for Fools to join a 75 minute online independent market research forum on 15th / 16th December.

To find out more and express your interest please click here

How To Join Britain’s ISA Millionaires

Learn how you really can make a million from ISA investing.

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.

Would you believe that there are already around 200 ISA millionaires in the UK?

Including the PEPs and TESSAs that preceded them, these tax-free investment vehicles have been in existence for 30 years now, with PEPs first introduced in the 1986 budget and the complementary TESSAs joining them in 1990.

It’s a fair guess that a good number of those ISA millionaires have been in it right from the start, transferred their PEPs and TESSAs to ISAs, and used their full allowances every year. And if that’s what can be achieved in 30 years, just imagine what heights you could reach over a full lifetime of investing!

What 30 years can bring

First, let’s think about what you might accumulate over the next 30 years and see if you could match these ISA millionaires. We’ll assume you’re able to use up your entire ISA allowance of £15,240 every year, investing it in 12 monthly installments of £1,270. How much would that bring in?

It all depends on the annual rate of return you can get, and if you stashed your savings in a cash ISA offering 2% annual interest (and a lot of them offer less than that), you’d finish your 30-year stretch with approximately £625,000 in the bag. Of that, £457,000 would be your own contributions with the remaining £168,000 coming from compound interest, and you might not think that’s too bad.

But what if you invest in shares instead, and reinvest any dividends you earn? An average annual return of 6% per year including dividends isn’t at all an unreasonable expectation (and I’d say it’s probably quite conservative). Some years you’d do better than that, others not as good, and some years you’d actually lose money — but with 30 years at your disposal, those short-term ups and downs will even-out and it’s the long-term average that counts.

With an average of 6% a year from shares, your ISA value would grow to around £1,244,000, easily getting you into the ISA millionaires club. What’s more, instead of the £168,000 in interest from a cash ISA, you’d be £787,000 in profit from share price appreciation and reinvested dividends!

A full life of investing

Now let’s extend our ‘what if?’ thinking a little further. It’s obviously unrealistic for the vast majority of us to use our full ISA allowance from the day we reach 18, so I’ll go with the following scenario…

Firstly, your parents start a Junior ISA for you when you’re born and invest the full £4,080 annual allowance, then when you reach 18 it converts to a standard ISA and you manage to invest £500 a month until you reach the age of 30. From then on, you use up your full allowance every year for the next 30 years. How much do you think you might have to celebrate your 60th birthday, assuming the same 6% return each year from shares? Go on, have a guess before you look down and find out…

Would you be surprised to learn that, through your ISA investments, you’d end up with a cool £3.35m, all tax free? The same plan, only invested in a 2% cash ISA, would fall short of the million pound target with a total of just £975,000.

Convinced yet?

The lesson is clear. If you want to reach millionaire status, invest as much of your annual ISA allowance as you can, start as early as you can — and put it in shares!

More on Investing Articles

Young woman holding up three fingers
Investing Articles

Want to start investing in 2026? 3 things to get ready now!

Before someone is ready to start investing in the stock market, our writer reckons it could well be worth them…

Read more »

Investing Articles

Can the stock market continue its strong performance into 2026?

Will the stock market power ahead next year -- or could its recent strong run come crashing down? Christopher Ruane…

Read more »

Businessman hand stacking money coins with virtual percentage icons
Investing Articles

Here’s how someone could invest £20k in an ISA to target a 7% dividend yield in 2026

Is 7% a realistic target dividend yield for a Stocks and Shares ISA? Christopher Ruane reckons that it could be.…

Read more »

A quiet morning and an empty Victoria Street in Edinburgh's historic Old Town.
Investing Articles

How little is £1k invested in Greggs shares in January worth now?

Just how much value have Greggs shares lost this year -- and why has our writer been putting his money…

Read more »

Businessman using pen drawing line for increasing arrow from 2024 to 2025
Investing Articles

This cheap FTSE 100 stock outperformed Barclays, IAG, and Games Workshop shares in 2025 but no one’s talking about it

This FTSE stock has delivered fantastic gains in 2025, outperforming a lot of more popular shares. Yet going into 2026,…

Read more »

Close-up of British bank notes
Investing Articles

100 Lloyds shares cost £55 in January. Here’s what they’re worth now!

How well have Lloyds shares done in 2025? Very well is the answer, as our writer explains. But they still…

Read more »

Thoughtful man using his phone while riding on a train and looking through the window
Investing Articles

How much do you need in an ISA to target £2,000 a month of passive income

Our writer explores a passive income strategy that involves the most boring FTSE 100 share. But when it comes to…

Read more »

Investing Articles

£5,000 invested in a FTSE 250 index tracker at the start of 2025 is now worth…

Despite underperforming the FTSE 100, the FTSE 250 has been the place to find some of the UK’s top growth…

Read more »