How long does it really take to become an ISA millionaire?

Money

There are more than 5,000 ISA millionaires in the UK

Holly MeadMoney writerFriday 21 November 2025 14:25 GMTComments

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Millionaire status might not happen instantly for Isa savers, but is certainly possible over time - and even those investing small amounts can build pots that Del Boy would have been envious of.

There are more than 5,000 Isa millionaires in the UK - savers who have squirrelled away enough in their Isa to get to seven figures. Is it possible to join their ranks?

Individuals can put up to £20,000 a year in an Isa, which can be put either in cash or invested, and any gains are tax-free.

Those hoping to reach millionaire status will need to invest; over the long-term, investing in the stock market has historically grown your money at a much greater rate than putting it in a cash savings account.

Some 94 per cent of Isas worth £1m or more are in stocks and shares Isas, according to analysis of HMRC data by Murphy Wealth. The rest are split, between cash and investments.

How long does it take to become an ISA millionaire?

Someone able to invest their full £20,000 Isa allowance every year would reach millionaire status within 22 years, assuming they achieved annual returns of 6 per cent.

But it is possible to do it with smaller amounts too.

Those able to invest £1,000 a month would reach £1m within 30 years, assuming the same annual return. Saving £500 a month would get you there inside 40 years.

If that seems a long time to wait, don’t be discouraged: the average Isa millionaire is 73 years old, according to Interactive Investor. Some 67 per cent are male. They have, on average, 41 per cent of their money in investment trusts, 35 per cent in individual shares, and just 5 per cent in cash.

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How do you invest your way to a million?

To get started, you will need to open a stocks and shares Isa. There are plenty of companies that offer these - be sure to compare the fees, make sure they are regulated, look at reviews, and consider the range of investments on offer before choosing.

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In an ideal world, you would be able to invest your full Isa allowance at the start of every tax year - but this is not realistic for many people.

Instead, set up a regular investing plan. This is a direct debit which invests a set amount each month, and is a great habit to get into.

The sooner you get started, the better. The longer your money is in the stock market, the more it can grow - and the more you can benefit from compound interest, where you earn interest on the gains you have already made and this boosts your returns. Richard Hunter, head of markets at Interactive Investor, explains: “Compounding is the effect of an initial lump sum plus interest earned, and then effectively interest on that interest. Over time, it becomes an increasingly powerful engine of growth.”

For example, if you invested £1,000 and it grew by 6 per cent, you would gain £60 and now have £1,060. If it grew by the same amount the following year, you would gain £63.60 and have £1,123.60, and so on - so you earn more each year even if you don’t invest any more.

Essentially, this means the earlier you start investing, the easier it is. Someone who invested £4,400 a year from age 20, and increased their contributions by 2 per cent a year (meaning they would invest £4,488 in the second year and so on), would become a millionaire by age 65, according to Interactive Investor. This assumes annual returns of 5 per cent.

If you waited until age 30 to start, you’d need to invest £8,200 in the first year, and increase this by 2 per cent a year, to reach millionaire status by age 65. Those who waited until age 40, would need to invest £16,400 in the first year.

Where to invest?

Looking at how Isa millionaires invest their money could help you get there faster. The average Isa millionaire achieved a return of 11.2 per cent in 2024, according to Interactive Investor.

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The 10 most common investments of Isa millionaires using Interactive Investor include a mix of funds, investment trusts and direct shareholdings. These include Alliance Witan, an investment trust which invests in companies across the globe, including Amazon, Mastercard and Diageo. It has returned 40 per cent over three years.

Scottish Mortgage, another investment trust, is also a popular option but is a racy choice as it can invest in private companies, which are not yet on the stock market. Its top holdings include SpaceX, Spotify and Ferrari, and it has returned 47 per cent over three years.

Legal & General, Aviva, BP, National Grid, Shell and GlaxoSmithKline are among the most popular individual stocks held by Isa millionaires. These are big FTSE 100 businesses, prized for their steady growth and for paying regular dividends.

Among the top investments of Isa millionaires using Hargreaves Lansdown, are two tracker funds - a type of low-cost fund that copies a chosen stock market.

These include Legal & General European Index, which invests in hundreds of European companies including Novo Nordisk and ASML and has returned 50 per cent over three years, and Legal & General Global Technology Index Trust, which backs big tech names including Apple, Microsoft and Meta and has returned 152 per cent over three years.

While looking at how Isa millionaires invest their money can provide ideas, it is important to consider your own requirements. Consider your personal risk appetite, how long you are planning to invest for, and what your overall goals are - then let time and consistency do the heavy lifting.

When investing, your capital is at risk and you may get back less than invested. Past performance doesn’t guarantee future results.