ISA Guide 2025–26: Types, Allowances & Rules

What is an ISA?

An Individual Savings Account (ISA) is a government-approved wrapper that lets you save or invest money completely free of UK tax. Interest earned inside a Cash ISA, dividends inside a Stocks & Shares ISA, and capital gains inside any ISA are all ignored by HMRC — they don't appear on your tax return and they don't count towards any of your other allowances.

The key restriction is the annual subscription limit: in 2025–26 you can pay in a maximum of £20,000 across all your ISAs combined. This limit has been frozen since 2017.

The five types of ISA

1. Cash ISA

The simplest ISA: a savings account where interest is earned tax-free. From April 2024 you can open multiple Cash ISAs in the same tax year, which is useful for moving money between providers chasing better rates. The best easy-access Cash ISA rates in 2025 were around 4.5–5%.

Good for: emergency funds, short-term savings goals, risk-averse savers who don't want market exposure.

2. Stocks & Shares ISA

You invest in funds, shares, investment trusts, or bonds within the ISA wrapper. Dividends and capital gains are tax-free regardless of amount. There's no CGT, no dividend tax, and the income doesn't affect your personal allowance.

Over long time horizons, equities have historically outpaced Cash ISA rates — but you can lose money, and the value of your investments can go down as well as up. Good for: long-term goals (5+ years), people who've used up their dividend allowance and personal savings allowance elsewhere.

3. Lifetime ISA (LISA)

Available to adults aged 18–39. You can save up to £4,000 per year (which counts within your £20,000 allowance), and the government adds a 25% bonus — up to £1,000 per year — on top. The bonus is paid monthly and can be invested or kept as cash within the LISA.

The catch: you can only withdraw the money penalty-free to buy your first home (purchase price up to £450,000) or when you turn 60. Withdrawing for any other reason before 60 incurs a 25% government withdrawal charge — which is applied to the full withdrawal including the bonus, meaning you can end up with less than you put in.

Good for: first-time buyers who are confident they won't need the money before 60, or those who want a government-boosted supplement to their pension.

4. Junior ISA (JISA)

A tax-free savings account for children under 18. Parents or guardians open the account; the child controls it from age 16 and can withdraw from age 18. The annual JISA allowance for 2025–26 is £9,000 — separate from the adult £20,000 limit. You can hold a Cash JISA, a Stocks & Shares JISA, or one of each.

5. Innovative Finance ISA (IFISA)

Allows peer-to-peer lending or crowdfunding investments to be held within an ISA wrapper. Higher potential returns but significantly higher risk than Cash or Stocks & Shares ISAs — these are not covered by the Financial Services Compensation Scheme (FSCS) in the same way, and platforms can fail. Most people should treat this as a specialist option rather than a core ISA choice.

The £20,000 annual ISA allowance

The £20,000 allowance resets each tax year on 6 April. You cannot carry unused allowance into the next year. Since April 2024, you can open and contribute to multiple ISAs of the same type in a single tax year, giving you more flexibility to shop around.

What ISA income is tax-free?

Inside an ISA, the following are completely tax-free and do not need to be reported on a tax return:

• Interest on cash savings
• Dividends from shares or funds
• Capital gains when you sell investments
• Rental income from REITs held inside the ISA

Crucially, none of this income counts towards your adjusted net income, so it won't trigger the personal allowance taper (for those earning near £100,000), affect your High Income Child Benefit Charge threshold, or erode your personal savings allowance.

Withdrawals and flexibility

You can withdraw money from a Cash ISA or Stocks & Shares ISA at any time without losing the tax benefit on existing funds. However, the withdrawn amount does not restore your annual allowance unless you're in a "flexible ISA" — a specific account type that lets you replace withdrawn amounts in the same tax year. Not all ISA providers offer flexible ISAs, so it's worth checking before withdrawing large sums if you intend to re-subscribe.

The LISA is a different story: withdrawals outside the qualifying rules (first-home purchase or retirement at 60+) trigger a 25% withdrawal penalty, effectively removing the government bonus plus a portion of your own contributions.

ISA vs pension: which is better?

The main advantages of pensions over ISAs are: contributions receive tax relief at your marginal rate (so a higher-rate taxpayer gets 40p of tax back for every 60p they contribute), and employer contributions — free money you can't get inside an ISA.

The main advantages of ISAs over pensions are: no tax on withdrawals (pension income is taxable), full flexibility on when and how much to withdraw, no lifetime or annual restrictions tied to earnings, and no minimum age to access funds (except the LISA).

For most people, the answer is: max employer pension matching first, then use ISA allowance, then consider additional pension contributions if you're a higher-rate taxpayer.

Transferring ISAs

You can transfer money from one ISA to another without it counting against your annual allowance, as long as the transfer is done properly through the providers (not by withdrawing cash yourself and re-depositing it). You can transfer current-year ISA subscriptions to a different provider, and you can also transfer previous years' ISA savings.