I’d drip-feed £333 a month into a Stocks and Shares ISA to make a million

A £1m Stocks and Shares ISA may seem like a ridiculous dream. But Tom Rodgers explains how it’s actually simple by following these rules.

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.

It’s a fact of life — and especially in investing — that there’s always a pay-off between time and money. But today I’ll show you the exact calculations you need to become a Stocks and Shares ISA millionaire.

With an initial investment of just £3,000, anyone can do it with the right rate of return.

At a very achievable 10% rate of return per year, you can turn a few grand into a million quid. With some outstanding performers, 10% may start to look like a very conservative number indeed.

So what’s the calculation, and how do you get there?

Simple rules

Building a Stocks and Shares ISA from decent to outstanding only requires one thing.

Consistency.

It’s one of the hardest things to do. It’s all very well dumping a wad of cash into your Stocks and Shares ISA just once. But if that doesn’t happen every month, you lose out on the real benefits of consistent investing.

When you do this, you get a huge investing advantage: pound cost averaging.

This means buying via your Stocks and Shares ISA when the market rates companies highly, and also when it rates them less well. It means at some points in the year you’ll get better value from buying shares at a relatively low price. And this will even out any points when you pay a relatively higher price for your shares.

In general it’s just a cleverer way to buy shares than all at once.

A £1m Stocks and Shares ISA

With £3,000 to start, adding £333 per month at a 10% rate of return will get you to the £1m threshold in 33 years. So if you’ve just turned 40, that means a few years after you retire, you’ll hit a seven-figure Stocks and Shares ISA.

You might think that by having a much larger starting amount, it’s much faster to create a £1m Stocks and Shares ISA. But that’s not strictly true. This demonstrates the power of regular investing.

Take for example a hefty £12,000 lump sum, and our original amounts of an extra £333 a month at 10% annual return. How much quicker do we reach the magic figure?

Only two years earlier.

Speeding up

If you’re shorter on time, a better option is to raise your regular monthly amounts.

It’s less of a burden for most of us to scrape together an extra couple of hundred pounds a month than it is to suddenly find £8k or £10k in one go.

With a £3,000 lump sum, a 10% rate of return and £633 a month, for example, you’ll reach £1,000,000 in your Stocks and Shares ISA in 27 years.

That’s six full years sooner than with £333 a month. If you have a couple of good years and your rate of return averages out a little higher, you’ll shave a few more years off too.

Making a million

A UK Stocks and Shares ISA has a maximum allowable limit of £20,000 per year. Breaking that down across 12 months gives us a maximum per-month allowance of £1,666.66.

I don’t know many people who can afford to put multiple thousands of pounds into their retirement fund every month, but if you can, great. I would start today and never look back.

Many investors are only interested in short-term gains. But if you can set a plan and stick to it long term? That’s where real wealth comes from.

TomRodgers 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.

More on Investing Articles

Lady wearing a head scarf looks over pages on company financials
Investing Articles

Is April a good time to start buying shares?

Wondering whether now's a good time to start buying shares to build wealth? History suggests it is, says Edward Sheldon.

Read more »

A senior group of friends enjoying rowing on the River Derwent
Investing Articles

How much passive income could a Stocks and Shares ISA pump out every year?

Regular investing inside a Stocks and Shares ISA could lead to the equivalent of £141 a week in tax-free passive…

Read more »

Fans of Warren Buffett taking his photo
Investing Articles

With the FTSE 100 down 5%+ investors should remember this legendary quote from Warren Buffett

Warren Buffett is widely regarded as the greatest investor of all time. And he says that the best time to…

Read more »

Inflation in newspapers
Investing Articles

1 FTSE 100 stock that could benefit from higher inflation

For most companies, inflation is a risk. But for one FTSE 100 firm, higher input costs could be an opportunity…

Read more »

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

The 2026 stock market sell-off could be a rare opportunity to build wealth in an ISA

The recent stock market sell-off has led to some shares falling 20% or more. This could be a great opportunity…

Read more »

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

It’s down another 13%! Analysts were dead wrong about the Greggs share price

The Greggs share price continues to fall and analysts have been revising their share price targets down further. Dr James…

Read more »

Burst your bubble thumbtack and balloon background
Investing Articles

Is the stock market about to reach breaking point?

Private credit has a problem with the emergence of artificial intelligence. And it could be set to create issues across…

Read more »

BUY AND HOLD spelled in letters on top of a pile of books. Alongside is a piggy bank in glasses. Buy and hold is a popular long term stock and shares strategy.
Investing Articles

A once-in-a-decade chance to buy this S&P 500 stock?

As investors focus on oil prices and the conflict in Iran, Stephen Wright's looking at potential opportunities in the S&P…

Read more »