The government has confirmed one of the most significant changes to ISA rules in a generation. From 6 April 2027, UK savers under the age of 65 will only be able to contribute £12,000 per year into a Cash ISA — down from the current £20,000 limit.
The remaining £8,000 of the annual ISA allowance will be reserved for Stocks and Shares ISAs. Read on for our complete The 2027 Cash ISA Rule Change breakdown.
This change has major implications for millions of UK savers who rely on Cash ISAs to grow their money tax-free without investment risk. Here is everything you need to know — and what you should do before April 2027.
2027 cash ISA rule change — What Exactly Is Changing?
Currently, every UK adult aged 18 and over can save up to £20,000 per tax year across ISA products, and that entire £20,000 can go into a Cash ISA if you choose. From the 2027/28 tax year onwards:
- Under 65s: Maximum Cash ISA contribution drops to £12,000 per year
- Over 65s: The full £20,000 allowance can still go into a Cash ISA
- The total annual ISA allowance remains £20,000 — it is only the split between cash and stocks that changes
- The remaining £8,000 can go into a Stocks and Shares ISA, Innovative Finance ISA, or Lifetime ISA
The government’s stated aim is to encourage more UK savers to invest in the stock market rather than hold cash, which historically delivers higher long-term returns. Critics argue the change removes freedom of choice and penalises cautious or lower-income savers who cannot afford to take investment risk.
Why Does This Matter So Much?
Cash ISAs are the most popular savings product in the UK for good reason. They offer:
- Tax-free interest — you pay zero income tax on the interest you earn, no matter how much it is
- Capital guarantee — unlike a Stocks and Shares ISA, your money cannot fall in value
- FSCS protection — up to £85,000 per institution
- Flexibility — many modern Cash ISAs (like Trading 212 and Moneybox) allow flexible withdrawals and redeposits
For savers who prioritise security over growth — particularly those approaching retirement, those saving for a house deposit, or those with a shorter time horizon — Cash ISAs are often the right choice. Reducing the annual limit cuts into that security.
The financial impact is real: on a 4.5% Cash ISA, the difference between saving £20,000 and £12,000 per year is £360 in tax-free interest annually. Over five years, that compounds to over £2,000 in lost tax-free growth.
What Are the Best Cash ISA Rates Right Now? (March 2026)
With one tax year remaining before the new rules take effect, ISA season 2026 is more important than ever. The top Cash ISA rates available right now are:
| Provider | Rate (AER) | Type | Min Deposit |
|---|---|---|---|
| XTB | 6.00% | Easy access (90-day bonus) | £1 |
| Trading 212 | 4.68% | Flexible easy access | £1 |
| Chip | 4.58% | Easy access | £1 |
| Moneybox | 4.26% | Easy access (3 free withdrawals/year) | £500 |
| Nationwide | 4.05% | Easy access | £1 |
| Skipton Building Society | 4.20% | Easy access | £1 |
Note: XTB’s 6% rate includes a 90-day bonus — after the bonus period ends, the rate reverts to a lower standard rate. Always check the post-bonus rate before opening. Trading 212 at 4.68% is the strongest standard easy-access rate with no hidden conditions.
The Two Tax Years That Matter Most: 2025/26 and 2026/27
Here is the timeline every UK saver under 65 needs to understand:
Tax Year 2025/26 (ending 5 April 2026)
- Full £20,000 Cash ISA allowance available
- Deadline: 5 April 2026 — unused allowance is lost forever
- Action: Maximise your contribution now if you haven’t already
Tax Year 2026/27 (6 April 2026 to 5 April 2027)
- Full £20,000 Cash ISA allowance still available — this is the last full year under current rules
- Deadline: 5 April 2027
- Action: Plan to maximise again — this is your final chance at the full allowance
Tax Year 2027/28 onwards (from 6 April 2027)
- Cash ISA allowance for under-65s drops to £12,000
- Remaining £8,000 must go into other ISA types
If you can contribute the full £20,000 in both 2025/26 and 2026/27, you will have sheltered £40,000 in tax-free cash savings before the rules change — money that will continue to earn interest tax-free indefinitely, regardless of the new limits.
How Much Could You Lose by Waiting?
Let’s put numbers to the cost of inaction. Assume you earn 4.5% on your Cash ISA and you are under 65:
| Scenario | Annual Contribution | Annual Tax-Free Interest |
|---|---|---|
| Current rules (to April 2027) | £20,000 | £900 |
| New rules (from April 2027) | £12,000 | £540 |
| Difference per year | £8,000 less | £360 lost annually |
That £360 compounds. Over ten years at 4.5%, the savers who maximised their allowance in 2025/26 and 2026/27 will have a significantly larger tax-free pot — and they’ll be earning interest on money that’s protected from income tax permanently.
What If You Can’t Afford to Maximise?
Not everyone has £20,000 to save each year — and that is completely understandable.
The principle still applies at smaller amounts. Even contributing an extra £1,000 to your ISA before 5 April is £1,000 more sheltered from tax permanently.
Practical steps if you can’t contribute the full amount:
- Contribute whatever you can before 5 April to use this year’s allowance
- Consider using savings currently in non-ISA accounts — transferring taxable savings into a Cash ISA shelters future interest from tax
- If you receive a bonus, inheritance, or any lump sum before 5 April, prioritise the ISA before putting money anywhere else
- Set a monthly direct debit into your Cash ISA from 6 April 2026 to build toward the £20,000 limit for 2026/27
Should You Switch to a Stocks and Shares ISA Instead?
The government’s policy change is explicitly designed to nudge savers toward Stocks and Shares ISAs. For some savers, this is the right move — but not for everyone.
A Stocks and Shares ISA makes sense if:
- You are investing for 5 years or more — the stock market needs time to recover from downturns
- You can tolerate your balance falling in value in the short term
- You are saving for retirement or another long-term goal
- You already have 3–6 months of expenses in an easily accessible cash account
A Cash ISA still makes sense if:
- You need the money in under 5 years (house deposit, emergency fund, etc.)
- You cannot afford to see your savings fall in value
- You are close to or in retirement and cannot recover from a market drop
- You want guaranteed tax-free returns without market risk
The good news: you do not have to choose. From April 2027, under-65s can split their allowance — £12,000 into a Cash ISA and £8,000 into a Stocks and Shares ISA in the same tax year. Many financial advisers recommend exactly this approach: cash for security and short-term needs, equities for long-term growth.
What About Existing ISA Balances?
Here is the crucial point that many people miss: the rule change only affects new contributions, not existing balances. Money already in your Cash ISA will continue to earn interest tax-free indefinitely, regardless of the new limits. The tax-free status of your existing pot is permanent.
This means every pound you put into a Cash ISA before April 2027 is protected tax-free forever — even when the new lower limits apply in future years.
Transferring Old ISAs: Don’t Leave Money Behind
Many UK savers have Cash ISAs sitting with old providers earning low rates — sometimes 0.5% or less. You can transfer these to a higher-rate provider without losing your tax-free status or counting against your annual allowance.
How ISA transfers work:
- Find a better-rate provider — Moneybox and Trading 212 both accept ISA transfers
- Apply to open an ISA with the new provider and request a transfer
- The new provider handles the transfer process — do not withdraw the money yourself, as this loses the tax-free wrapper
- The transfer typically takes 15 working days for cash ISAs
Moneybox is particularly strong for ISA transfers, offering its standard 4.26% AER rate on transferred balances. If you have old ISAs from previous years sitting with a big bank at 1–2%, moving them to Moneybox or Trading 212 could add hundreds of pounds in additional interest annually.
Key Dates to Diary
- 5 April 2026 — Tax year 2025/26 ends. Deadline to use your full £20,000 Cash ISA allowance
- 6 April 2026 — New tax year 2026/27 begins. Full £20,000 allowance resets
- 5 April 2027 — Final day to use the full £20,000 Cash ISA allowance under current rules
- 6 April 2027 — New rules take effect. Cash ISA allowance for under-65s drops to £12,000
Frequently Asked Questions
Can I still open a new Cash ISA after April 2027?
Yes. Cash ISAs will still exist after April 2027.
The change only affects how much you can contribute each year — the £12,000 limit for under-65s, rather than £20,000.
Does the rule change affect existing ISA balances?
No. Money already in your Cash ISA continues to earn tax-free interest indefinitely. Only new contributions from April 2027 are subject to the new £12,000 limit.
What if I am 64 now — do I still get the lower limit from April 2027?
The rules as announced apply to under-65s from 6 April 2027. If you turn 65 during the 2027/28 tax year, the rules on when the higher limit applies to you have not yet been fully clarified — check GOV.UK closer to the date.
Can I put £12,000 in a Cash ISA and £8,000 in a Stocks and Shares ISA in the same year?
Yes — from April 2027, splitting your allowance between ISA types in the same tax year will be possible. This is already the case under current rules.
The Bottom Line
The 2027 Cash ISA rule change is not a reason to panic — but it is a reason to act quickly. The two tax years between now and April 2027 represent your last opportunity to shelter the full £20,000 in a Cash ISA annually.
Every pound you contribute before that deadline is protected tax-free forever.
With top Cash ISA rates at 4.68% (Trading 212) and 4.58% (Chip), there has rarely been a better time to maximise your ISA allowance. The combination of strong rates today and shrinking allowances tomorrow makes acting now the clearest financial decision most UK savers can make.
Rates correct as of March 2026. Always verify current rates directly with providers.
This article is for informational purposes only and does not constitute financial advice. The ISA allowance changes described reflect government announcements as of March 2026 — always check GOV.UK for the most current information.