Cash ISA vs Stocks and Shares ISA: What Is the Difference?

In the 2026-27 tax year, a Cash ISA holds savings, such as money in bank and building society accounts, while a Stocks and Shares ISA can hold shares, funds and bonds, so its value can rise or fall. gov.uk says you do not pay tax on interest on cash in an ISA, or on income or capital gains from investments in an ISA. Both types count towards the same £20,000 yearly allowance.

The site's rules data was last checked against gov.uk on 26 September 2026. Figures typed in this guide may not yet reflect a later change, and the descriptions of gov.uk pages are summaries that may also lag. The current figures are on the ISA rules at a glance page. General information only, not financial advice.

What is a Cash ISA?

A Cash ISA works like a savings account: money is deposited and earns interest that is free of tax. The GOV.UK page on how ISAs work says cash ISAs can include savings in bank and building society accounts and some National Savings and Investments products. It is the simpler, lower-risk option.

Safety: FSCS deposit protection is up to £120,000 per eligible person, per bank, building society or credit union. The FSCS pages read for this guide do not name ISAs, so ask your provider or FSCS whether a given ISA is covered.
Access: many Cash ISAs offer instant or short-notice access, and some have fixed terms.
Returns: interest rates can be fixed or variable.
Often used for: short-term savings, emergency funds, or money that may be needed soon (an illustration, not a rule).

The Cash ISA Calculator shows how savings could grow at an assumed rate. The guide to how interest rates affect Cash ISAs explains how and why Cash ISA rates change.

What is a Stocks and Shares ISA?

gov.uk says stocks and shares ISAs can include shares in companies, unit trusts and investment funds, corporate bonds, government bonds and long-term asset funds (GOV.UK: how ISAs work). Returns come from dividends and capital growth, so the balance can rise or fall.

Growth potential: investments have historically returned more than cash over long periods, which is not guaranteed.
Risk: the value can go down as well as up, and there is no FSCS protection against market losses.
Often used for: long-term goals such as retirement, where there is time to wait out short-term falls (an illustration, not a rule).
Flexibility: the holder can choose their own investments or use a managed fund.

The Stocks and Shares ISA Calculator models growth at assumed returns. See also what UK investors actually earn from a stocks and shares ISA for how charges and asset mix affect returns.

How do the two compare at a glance?

Risk: Cash is low. Stocks and Shares is medium to high.
Typical returns: Cash gives lower, fixed or variable interest. Stocks and Shares has higher long-term potential, but variable.
Access: Cash is usually instant or short notice. Stocks and Shares may take a few days to sell and withdraw. gov.uk says you can take your money out of an ISA at any time without losing any tax benefits, and to check the terms of your ISA for rules or charges (GOV.UK: withdrawing your money).
Protection: Cash has FSCS deposit protection up to £120,000 per eligible person, per bank, building society or credit union; the FSCS pages read for this guide do not name ISAs, so ask your provider or FSCS whether a given ISA is covered. Stocks and Shares has no FSCS protection against market losses.
Often used for: Cash for short-term savings and emergencies. Stocks and Shares for long-term growth and retirement planning (an illustration, not a rule).

A worked example: the same amount under assumed outcomes

This example uses assumed figures to show the arithmetic. They are not forecasts, not quotes from any product, and they ignore charges. £10,000 is held for ten years with interest or growth added once a year.

Cash at an assumed 3% a year: £10,000 × 1.03 to the power of 10 is about £13,439.
Stocks and Shares at an assumed 5% a year: £10,000 × 1.05 to the power of 10 is about £16,289.
Stocks and Shares with an assumed fall of 20% in one year: £10,000 becomes £8,000 at that point, before any recovery.

The first two lines show why people look at growth potential. The third shows why the risk matters: real returns are not steady, and a Stocks and Shares ISA can be worth less than was paid in.

What do people weigh up when choosing between the two?

Time horizon (an illustration, not a rule): some people think of a Cash ISA for shorter periods and a Stocks and Shares ISA, with more growth potential, for longer ones such as five years or more. It depends on the person.
Risk tolerance: some people who want lower risk consider a Cash ISA, and some who are comfortable with ups and downs consider a Stocks and Shares ISA (an illustration, not a rule).
Purpose (an illustration, not a rule): some people use a Cash ISA for an emergency fund or short-term goal and a Stocks and Shares ISA for retirement or long-term goals.
Inflation: Cash ISA returns may not keep pace with inflation over time. Stocks and Shares ISA returns can be higher or lower than inflation and are not guaranteed.

What is the new cash ISA limit?

Regulations made on 10 September 2026 (SI 2026/1018, regulation 6, read on legislation.gov.uk on 6 October 2026) set a separate yearly limit on how much savers who are under 65 at the end of the tax year can pay into cash ISAs, lower than the overall ISA allowance, to apply from April 2027. The GOV.UK policy paper says the overall limit is retained and that the cash limit for investors aged 65 or over is not reduced. It also describes restrictions on transfers from stocks and shares and Innovative Finance ISAs into cash ISAs (GOV.UK: cash ISA limit reduction). The change is made in law and is not yet in force.

The Cash ISA Calculator page sets out the current limits and dates, and the calculator applies the cash limit for each tax year. The guide to the cash ISA changes from 2027 covers the detail.

Can a person hold both?

Yes. Many savers split their yearly allowance between a Cash ISA and a Stocks and Shares ISA. The guide on how to split your ISA allowance between cash and stocks and shares works through an example. The ISA Calculator models a single ISA, and the Advanced ISA Planner compares blended approaches side by side. For a third option, see the comparison of the Lifetime ISA vs stocks and shares ISA.

What to check about the allowance and the provider

gov.uk sets the allowance for each tax year, and the pages read describe no carry forward, so this guide does not assume an unused part is added to a later year. The ISA Allowance Checker and the ISA Contribution Split Planner can help work out how much has been used.
Is the ISA mix reviewed as goals and risk appetite change?
Is there an emergency fund held in cash? Some people keep one (an illustration, not a rule).
What are the platform and fund fees on a Stocks and Shares ISA? Fees reduce returns over time.
Is a move between providers made through the transfer process? gov.uk says that money withdrawn without using it cannot have that part of your tax-free allowance reinvested. See how to transfer ISA accounts.

What is the short summary of the differences?

Cash ISAs are lower risk and usually easy to access, subject to the account terms. Stocks and Shares ISAs offer higher long-term growth potential in exchange for risk. Which suits a person depends on their time horizon, how much risk they are comfortable with and what they are saving for.

Frequently asked questions

Can I have both a Cash ISA and a Stocks & Shares ISA?

Yes. You can pay into both in the same tax year, as long as your total contributions across all ISA types don't exceed your annual £20,000 allowance.

Which is safer, a Cash ISA or a Stocks & Shares ISA?

A Cash ISA is generally regarded as lower risk: your balance does not fall with markets, subject to the provider's terms and any FSCS cover. FSCS deposit protection is up to £120,000 per eligible person, per bank, building society or credit union. The FSCS pages read for this guide do not name ISAs, so ask your provider or FSCS whether a given ISA is covered. A Stocks & Shares ISA can lose value, though it has higher long-term growth potential.

Can I switch from a Cash ISA to a Stocks & Shares ISA?

Yes, you can transfer between ISA types. gov.uk says the transfer can be to a different type of ISA or the same type; if you withdraw the money without using the transfer process you will not be able to reinvest that part of your tax-free allowance again.

This guide does not constitute financial advice. Your personal situation, tax position, and savings goals may mean different strategies are appropriate. Consider speaking to a regulated financial adviser if you are uncertain.