ISAs let you save and invest up to £20,000 per year completely tax-free. Here is how each type works and how to make the most of your allowance.
An Individual Savings Account (ISA) is a tax-free wrapper provided by HMRC. Any interest, dividends, or capital gains earned inside an ISA are completely free from UK tax. You do not need to report ISA income on your self-assessment return.
The annual ISA allowance for 2025/26 is £20,000. This is the total you can pay in across all your ISA accounts in a single tax year (6 April to 5 April).
Cash ISA: Works like a savings account. Your interest is tax-free. Useful for short-term savings or emergency funds. Current best rates are around 4-5%.
Stocks and Shares ISA: Invest in funds, shares, bonds, and ETFs. All dividends and capital gains are tax-free. This is the most powerful ISA type for long-term wealth building — over 10+ years, investment returns typically outpace cash.
Lifetime ISA (LISA): For ages 18-39. Save up to £4,000/year and the government adds a 25% bonus (up to £1,000/year). Can only be used for a first home purchase or retirement after age 60. Early withdrawal incurs a 25% penalty.
Innovative Finance ISA: Holds peer-to-peer lending investments. Higher risk than cash but potentially higher returns. Less commonly used.
You can split your £20,000 allowance across different ISA types in any combination. For example, you could put £16,000 into a Stocks and Shares ISA and £4,000 into a Lifetime ISA.
You can only pay into one of each type per tax year. For example, you cannot have two Stocks and Shares ISAs receiving new contributions in the same year (but you can hold multiple from previous years).
Unused allowance does not carry forward. If you only use £10,000 this year, the remaining £10,000 is lost forever. Use it or lose it.
A couple can shelter £40,000 per year between them (£20,000 each). Over 10 years, that is £400,000 in tax-free wrappers — generating potentially tens of thousands in tax-free returns.
Pensions offer tax relief on contributions (20%, 40%, or effective 60% in the trap band). ISAs do not. For high earners, pensions are almost always better for retirement saving because of the upfront tax relief.
ISAs offer flexibility: you can withdraw at any time without penalty and there is no minimum access age. Pension money is locked until age 57 (from April 2028).
ISAs are better for inheritance: ISA assets pass to your estate and can be inherited by a spouse via an Additional Permitted Subscription (APS). Pensions pass outside your estate but are taxed as income if inherited after age 75.
The ideal approach for most high earners: maximise pension contributions first (especially in the 60% trap band), then use remaining savings capacity for ISAs.
You can transfer ISAs between providers without losing your tax-free status. Always use the formal ISA transfer process — never withdraw and re-deposit, as you will permanently lose that year's allowance on the withdrawn amount.
Cash ISA transfers must complete within 15 working days. Stocks and Shares ISA transfers can take up to 30 working days.
If you hold investments outside an ISA, you can sell them and immediately rebuy the same investments inside your ISA. This is called "bed and ISA" and it shelters future growth from tax.
Be aware: selling triggers a capital gains event. If your gain exceeds the £3,000 annual CGT exemption (2025/26), you will owe capital gains tax on the excess. Plan your bed and ISA transfers across multiple tax years to stay within the exemption.