The 2026 ISA: Everything UK Savers Need to Know This Tax Year.

The 2026/27 tax year is a pivotal moment for ISA savers. While the headline £20,000 allowance survives untouched for another twelve months, the Autumn Budget 2025 has set in motion the biggest structural change to Cash ISAs in years — and the Lifetime ISA is on borrowed time. If you save or invest tax-free in the UK, the decisions you make between now and 5 April 2027 will matter more than usual.

This guide explains the rules as they stand, what is changing and when, and how to think about your allowance in light of what's coming.

The headline numbers for 2026/27

The 2026/27 tax year runs from 6 April 2026 to 5 April 2027. For this year:

• The overall ISA allowance remains £20,000, which you can split across Cash ISAs, Stocks and Shares ISAs, Innovative Finance ISAs and a Lifetime ISA in any proportion you like.
• The Lifetime ISA sub-limit stays at £4,000 per year, with the government's 25% bonus paying up to £1,000 on top.
• The Junior ISA allowance is £9,000 per child, and it does not count towards an adult's £20,000.
• Allowances do not roll over. Any unused portion from the 2025/26 tax year (ending 5 April 2026) cannot be carried forward. If you don't use it, you lose it.

There is no cap on how much you can accumulate inside ISAs over your lifetime. The annual limit governs only what you can contribute each year; once money is inside the wrapper, all future interest, dividends and capital gains are permanently sheltered from UK tax.

The big change: Cash ISA limits from April 2027

The most significant announcement in the Autumn Budget 2025 was a reform of the Cash ISA, taking effect from 6 April 2027. The change does not affect the 2026/27 tax year directly, but it shapes how that year should be used.

From 6 April 2027, savers under 65 will face a new sub-limit on Cash ISA contributions. Your total annual ISA allowance will still be £20,000, but the way you can use it will change for those under 65: you'll be able to put up to £12,000 in a Cash ISA each tax year. The rest — up to £8,000 — could go into a Stocks and Shares ISA. Or, you can choose any combination that suits you, as long as you don't exceed £12,000 in a Cash ISA and your total across both types of ISAs doesn't go over the £20,000 total ISA allowance.

Savers aged 65 and over are exempt from the new cap. If you're aged 65 or over, your Cash ISA allowance will remain at £20,000 for the 2027/28 tax year. If you're turning 65 part-way through the 2027/28 tax year, the new rules on maximum deposits will be clarified after an industry consultation in 2026.

Crucially, the changes only apply to new contributions from 6 April 2027 onwards, so you still have this tax year and the next to save up to £20,000 in a Cash ISA tax-free, if that's right for you. Any money already saved in your Cash ISA from this year or previous years should stay protected and continue to earn tax-free interest.

The policy intent is clear: the Treasury wants to nudge younger savers from cash into investments. Whether that suits you depends on your time horizon, risk appetite and existing portfolio — but the practical implication is that the 2026/27 tax year, which begins on 6 April 2026, represents the final chance for younger savers to maximise Cash ISA contributions at the current £20,000 level.

Flexibility rules carried over from 2024

Two reforms introduced in April 2024 remain in force and are worth understanding, because they change how strategically you can run multiple accounts.

You can now hold and pay into more than one ISA of the same type in a single tax year, provided your total contributions stay within the £20,000 limit. This means you could open two Cash ISAs with different providers — one easy access, one fixed rate — and feed both from the same allowance.

You can also make partial transfers of current-year contributions between providers. Previously, transferring your current-year ISA required moving either all or none of your contributions. Now, you can transfer part of your Cash ISA to another provider. This makes it easier to chase better rates without having to move everything in one go.

One rule that has not changed: the Lifetime ISA is still a once-per-year account. You can only pay into one Lifetime ISA each tax year.

The Lifetime ISA is being phased out

The Autumn Budget 2025 also confirmed that the Lifetime ISA's days are numbered. Delivered by Chancellor Rachel Reeves on 26 November 2025, the Budget confirmed the government will consult on replacing the Lifetime ISA with a new, simpler first-time buyer savings product. Budget documents stated the consultation would take place in early 2026, with the new product expected to launch from April 2028.

The current rules remain in place for now. You must be aged 18–39 when you open (and pay into) your first Lifetime ISA. You can pay in up to £4,000 each tax year — this also counts towards your overall ISA allowance. You'll then get a 25% bonus, up to a maximum of £1,000 a year, on money you pay in. You can pay into a valid Lifetime ISA (and get the bonus) until your 50th birthday.

The funds can be used penalty-free for a first home costing up to £450,000, or accessed from age 60 for retirement. Any other withdrawal triggers a 25% government charge, which means you lose the bonus and approximately 6.25% of your own contributions.

If you're an eligible first-time buyer, opening a LISA before the April 2028 cut-off is generally still sensible — even with a token deposit. Once it's scrapped, new LISAs won't be available, but existing ones are expected to stay open under the same rules. Opening one now keeps your options open. The replacement product is expected to drop the retirement-saving option and focus solely on first-home purchases, so anyone who wants the dual-purpose flexibility should act under the current regime.

Why the wrapper matters more in 2026

ISAs have always been valuable, but two parallel changes to the wider tax system have made them more valuable still. The Capital Gains Tax annual exemption is now just £3,000, and the dividend allowance has shrunk to £500, meaning most people with investments outside ISAs will pay tax. Dividend tax rates are also rising from April 2026.

In practical terms, this means that any meaningful investment portfolio held outside an ISA is now likely to generate a tax bill, even for basic-rate taxpayers. The ISA wrapper, which used to be a nice-to-have for small investors, has become close to essential.

Practical priorities for the 2026/27 tax year

For most savers, the planning checklist is short:

If you are under 65 and currently using a Cash ISA, the next two tax years (2025/26, which ended on 5 April 2026, and 2026/27) are your last chances to put a full £20,000 into cash at the £20,000 limit. If you have funds available, filling those allowances locks in tax-free status before the £12,000 cap arrives in April 2027.

If you are investing rather than saving, the £20,000 Stocks and Shares ISA allowance is unaffected by the 2027 changes. The new rules actually push more of the under-65 allowance towards investment ISAs, which is the Treasury's intention.

If you are a first-time buyer aged 18–39, opening a Lifetime ISA before April 2028 preserves access to the current bonus structure, even if you only contribute a small amount initially.

If you are 65 or over, none of the Cash ISA changes apply to you, and your £20,000 Cash ISA allowance continues indefinitely under current rules.

If you hold old ISAs paying poor rates, the partial transfer rules and the ability to hold multiple same-type ISAs make it easier than ever to consolidate or shift to better-paying accounts without sacrificing your tax-free status. Always use the official ISA transfer process — withdrawing and redepositing forfeits the wrapper.

A note on what isn't changing

It's worth ending on what has stayed the same, because the noise around the 2027 changes can obscure it. The overall £20,000 allowance is intact. Stocks and Shares ISAs are completely unaffected. Existing balances keep their tax-free status forever. Junior ISAs continue at £9,000. The spousal Additional Permitted Subscription on death still applies.

The ISA remains the most generous tax shelter most UK residents will ever have access to. The 2026/27 tax year is a year to use it deliberately, with one eye on what 2027 will bring.

This article is for general informational purposes only and does not constitute financial advice. Tax treatment depends on individual circumstances and may change in the future.