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Stocks & Shares ISA Calculator

Project the growth of your Stocks and Shares ISA and compare with Cash ISA returns over time.

Investment Details

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Past performance does not guarantee future results. The value of investments can go down as well as up.

Projected Growth

Stocks & Shares ISA Value

£458,000

After 20 years

Total Contributed

£205,000

Investment Growth

£253,000

Advantage over Cash

£137,353

Stocks & Shares ISA

£458,000

Growth: £253,000

Cash ISA

£320,648

Growth: £115,648

Year-by-Year Breakdown

YearContributedS&S ISACash ISA
1£15,000£16,050£15,600
2£25,000£27,874£26,624
3£35,000£40,525£38,089
4£45,000£54,061£50,013
5£55,000£68,546£62,413
10£105,000£157,672£132,265
15£155,000£282,676£217,250
18£185,000£380,689£276,841
19£195,000£418,038£298,315
20£205,000£458,000£320,648

Understanding Stocks and Shares ISAs

A Stocks and Shares ISA allows you to invest in a wide range of assets including funds, shares, bonds, and investment trusts, all within a tax-efficient wrapper. Any income (dividends) and capital gains earned within the ISA are completely free from UK tax, making it one of the most powerful savings tools available to UK investors.

The Power of Compound Growth

The key advantage of investing over saving in cash is the potential for compound growth over long periods. While cash savings earn a fixed interest rate, investments can grow through both capital appreciation and reinvested dividends. Over 20 or 30 years, this compounding effect can result in significantly larger returns, though it comes with greater short-term volatility.

Risk and Time Horizon

Investing in a Stocks and Shares ISA carries more risk than a Cash ISA, as the value of your investments can fall as well as rise. However, historically, equities have outperformed cash over periods of 10 years or more. The general guidance is to invest for at least 5 years to give your investments time to recover from any short-term market downturns.

Related Tools and Resources

Building a savings habit is one of the most effective ways to improve your financial wellbeing. You may also find our Compound Interest Savings Calculator useful for related calculations.

For a broader view of your finances, try the Compound Interest Calculator or the Take-Home Pay Calculator. All of our calculators are free to use and updated for the 2026/27 tax year where applicable.

Frequently Asked Questions

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