Still have your money in a cash ISA? Here’s why your retirement could be at risk

UK savers love the cash ISA. But this savings product has a key flaw, says Edward Sheldon.

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.

Despite the low interest rates on offer from cash ISAs, statistics show that many people in the UK continue to save their money in these products.

For example, according to HMRC, in the 2017/18 financial year 75% of all ISA contributions went into cash vaieties. Moreover, of the £608bn saved across all ISA products at the end of the 2017/18 financial year, 44% was saved this way.

There’s no doubt that theydo offer savers some advantages. For instance, any income generated within a cash ISA is tax-free. That’s a big plus, especially if you have a substantial amount of money saved in an ISA. Also, money saved within a cash product is secure so you’re not going to lose your savings. 

However, if you’re using one as a retirement savings vehicle, you need to be aware that because interest rates remain abysmally low, your money could be losing value in real-life spending terms over time. As such, your retirement could potentially be at risk.

Inflation can destroy your wealth 

The reason I say this is that even the best cash ISA rates right now are below the rate of inflation (the rise in the prices of goods and services over time). What that means is that money saved in a cash product is potentially losing purchasing power as the years go by. In real-life spending terms, it’s becoming less valuable.

For example, over the last six months, UK inflation has averaged around 2.28% per year, meaning that goods and services have risen at that annualised pace per year. In contrast, the best cash ISA rate currently is around 1.45%, according to Money Saving Expert (and that rate comes with restrictive conditions too).

This means that even if money is held in a such an ISA offering the best interest rate, it’s still not growing as fast as the general rise in prices of goods and services across the UK. Essentially, it’s losing its real-life purchasing power by around 0.8% per year.

Leaving money in that particular savings vehicle for a period of 10 or 20 years could therefore have devastating consequences. You could potentially reach retirement, only to discover that your money doesn’t buy as much as it does today.

How to grow your money faster than inflation

To avoid losing spending power over time, it’s important that your money grows at a rate that is above inflation. And one of the easiest ways to do this is to allocate some of your money to growth assets such as shares.

Shares are higher risk than cash savings, yet at the same time, they tend to provide much higher returns (around 7% to 10% per year on average over the long term) meaning that money invested in shares tends to grow at a rate above inflation over time.

Growing your money at 7% to 10% per year, as opposed to 1.45% per year through a cash ISA could make a big difference to your retirement savings over the long term.

These days, it’s easier than ever to get started with investing. Opening a stocks and shares ISA is a good place to start. If you’re looking to learn more about how to grow your money through stocks, you have come to the right place.

More on Investing Articles

This way, That way, The other way - pointing in different directions
Investing For Beginners

1 FTSE 250 stock I like and 1 I’ll avoid after the stock market correction

Jon Smith analyses the move lower in certain FTSE 250 companies over the past month and picks one that looks…

Read more »

Playful senior couple in aprons dancing and smiling while preparing healthy dinner at home
Investing Articles

Is April 2026 a great time to buy Lloyds shares?

Lloyds shares have been flying over the last two years. And there's one factor that could mean the bank continues…

Read more »

Young mixed-race couple sat on the beach looking out over the sea
Investing Articles

Want to aim for a £500 second income each month? Here’s how much it takes

Christopher Ruane digs into the numbers and mechanics that could let someone with no shares today build an annual second…

Read more »

Aston Martin DBX - rear pic of trunk
Investing Articles

Down 95%, what might it take for the Aston Martin share price to rise 2,000%?

The Aston Martin share price has collapsed. Our writer considers what it might take for it to regain some ground…

Read more »

Investing Articles

How are Diageo shares looking in April 2026?

It's been an eventful year so far, but what has the impact been for Diageo shares, and where might they…

Read more »

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

P/Es below 7! 3 staggeringly cheap shares despite yesterday’s rally

Investors who fear they have missed their opportunity to buy cheap shares as the stock market recovers might want to…

Read more »

ISA coins
Investing Articles

Want to know what UK investors have been buying in their ISAs?

Looking for stock, trust, and fund ideas this April? Royston Wild discusses what Brits have been stuffing in their Stocks…

Read more »

Mature Caucasian woman sat at a table with coffee and laptop while making notes on paper
Investing Articles

Why aren’t people buying Greggs shares by the bucketload?

Greggs' shares remain in the doldrums. But should Foolish investors consider pouncing while others won't? Paul Summers takes a fresh…

Read more »