Cash ISA or Stocks and Shares ISA: how to choose
A Cash ISA holds savings that do not fall in value. A Stocks and Shares ISA holds investments that can fall as well as rise. Which suits you depends on your time horizon, your need for access, and how much short-term loss you could tolerate.
The short answer
- Cash ISAs protect your capital day to day. Stocks and Shares ISAs can lose value, especially over short periods, but have more room to grow over longer ones.
- FSCS protects Cash ISA deposits up to £120,000 per person per authorised firm. FSCS protects Stocks and Shares ISA investments up to £85,000, and only if the firm itself fails, not if investments simply fall in value.
- From 6 April 2027, under-65s can put at most £12,000 of their £20,000 allowance into a Cash ISA, pushing more of the total toward Stocks and Shares, innovative finance or a Lifetime ISA.
- This page does not recommend either option or any provider. It sets out the trade-offs so you can weigh them against your own circumstances.
What is the real difference?
A Cash ISA is a savings account with a tax-free wrapper on top. The bank owes you back what you paid in, plus interest, and your balance does not fall because of market movements. A Stocks and Shares ISA is an investment wrapper: it holds shares, funds or similar assets whose price is set by the market, so your balance can rise, and it can also fall, including below what you originally put in.
Neither is inherently better. They do different jobs, and the right mix depends on what the money is for and when you are likely to need it.
How much risk can you take, and for how long?
Time horizon is usually the first practical question. Money you might need at short notice, an emergency fund, a house deposit due next year, a tax bill, sits more comfortably in cash, where the amount you can withdraw does not depend on market timing. Money you will not touch for many years has more time to recover from any short-term falls, which is one reason investing is generally considered better suited to longer horizons.
Access: how easily can you get your money?
Cash ISAs vary between easy access, where you can withdraw whenever you like, and fixed-rate or notice accounts, where early withdrawal can mean a lost-interest penalty or a wait. Stocks and Shares ISAs can usually be sold within a few working days, but what you actually receive depends entirely on the market price on the day you sell, not on the price when you bought or the price you might have got a week earlier. Quick access to a Stocks and Shares ISA does not mean quick access to a known amount.
The risk cash does not protect you from
A Cash ISA protects your capital in cash terms: £10,000 today is still £10,000 next year, plus whatever interest it earns. It does not protect the buying power of that money. If prices rise faster than your interest rate, your money is worth less in real terms even though the number in your account has gone up. This is a genuine risk of holding cash, just a quieter one than a market fall, because the balance itself never visibly drops.
A Stocks and Shares ISA carries the opposite trade-off: more visible short-term ups and downs, with the possibility, not the guarantee, of growth that outpaces rising prices over longer periods. Neither risk is inherently worse than the other. They are different risks, and which matters more to you depends on your time horizon again.
FSCS protection: what is actually covered?
This is one of the most commonly misunderstood parts of the comparison, so it is worth being precise.
| Cash ISA | Stocks and Shares ISA | |
|---|---|---|
| FSCS limit | £120,000 per person, per authorised firm | £85,000 per person, per firm |
| Changed | Raised from £85,000 on 1 December 2025 | Unchanged since 1 April 2019 |
| What it covers | The firm holding your deposit failing | The firm managing your investments failing |
| What it does not cover | N/A | Your investments simply falling in value |
The Stocks and Shares figure only pays out if the regulated firm itself collapses, for example through fraud or mismanagement, and cannot return your investments or their value. It is not insurance against a normal market fall, which is a risk you carry regardless of FSCS.
Cost and diversification
The two also differ in how your money is typically spread, and what it costs to hold it. A Stocks and Shares ISA usually holds pooled investments, funds or a spread of shares, so a single company’s performance rarely determines your whole result, though platform charges and fund charges reduce your return over time and are worth checking carefully before you choose. A Cash ISA is simpler: there is one figure that matters, the rate, and no ongoing charge for holding the money, though that same simplicity means there is no further growth mechanism beyond that rate.
Why is the government pushing people toward investing from 2027?
From 6 April 2027, savers who are 64 or under at the end of the tax year can put at most £12,000 of their £20,000 overall ISA allowance into a Cash ISA. The remaining £8,000, if you want to use your full allowance, has to go into a Stocks and Shares ISA, an Innovative Finance ISA, or a Lifetime ISA. Our full guide to the 2027 Cash ISA cap covers the change in detail. The government’s own factsheets describe the goal as encouraging retail investment and supporting better long-term returns for savers, alongside rules designed to stop cash simply being parked inside a non-cash ISA instead.
Savers who are 65 or over at the end of the relevant tax year are not affected by the £12,000 cap and keep the full £20,000 Cash ISA allowance.
Questions to ask yourself
Rather than a recommendation, these are the questions worth answering honestly before you decide where new money goes:
- When do you actually expect to need this money?
- How would you feel, practically, if its value fell by a noticeable amount shortly after you invested it?
- Do you already have a cash buffer for emergencies and short-term needs, separate from this decision?
- Are you trying to use your full £20,000 allowance, or is the Cash ISA limit from 2027 the only reason you are considering Stocks and Shares at all?
Tax treatment depends on your circumstances and may change.
Questions people ask
Which is safer, a Cash ISA or a Stocks and Shares ISA?
A Cash ISA is safer in the sense that your capital does not fluctuate with markets, and deposits are protected by FSCS up to £120,000 per person per authorised firm. A Stocks and Shares ISA can fall in value, including below what you paid in, and FSCS only steps in if the firm itself fails, not if your investments simply underperform.
How much FSCS protection does each type of ISA have?
Cash ISA deposits are protected up to £120,000 per person per authorised firm, a limit that rose from £85,000 on 1 December 2025. Stocks and Shares ISA investments are protected up to £85,000 per person per firm, a limit that has not changed since 1 April 2019, and that only applies if the firm managing your investments fails.
How long should I plan to hold a Stocks and Shares ISA before I need the money?
There is no fixed rule, but investing is generally considered better suited to money you will not need for several years, because share and fund prices can fall sharply over shorter periods and may not have time to recover before you need to withdraw.
Can I hold both types of ISA at once?
Yes. Cash ISAs and Stocks and Shares ISAs share the same overall £20,000 annual allowance, and you can split that allowance between them in whatever combination you choose, as long as the total does not go over £20,000.
Why is the government pushing people toward investing from 2027?
The stated aim, set out in the 2027 ISA reform factsheets, is to encourage a stronger retail investment culture and help savers get more from their money over the long term, by making the Cash ISA limit lower for under-65s while keeping the overall £20,000 allowance the same.
Can I move money between the two types of ISA?
Yes, transfers between ISA types are generally allowed, though the rules are changing. From 6 April 2027, transfers from a Stocks and Shares ISA into a Cash ISA will be blocked for savers under 65, while cash-to-stocks-and-shares transfers remain unaffected.