ISA Allowance 2026/27: £20,000 Tax-Free and How to Use It

As other tax-free allowances have been cut back, one has held firm and become more valuable than ever: the £20,000 ISA allowance. An ISA shelters your savings and investments from tax entirely, and in 2026/27 - with savings interest, dividends and capital gains all taxed more heavily - it is one of the simplest ways to keep more of your money. This guide explains the allowance, the ISA types, and how to make the most of yours.

Quick summary

• Annual allowance: £20,000 across all your ISAs
• Tax inside an ISA: none - interest, dividends and gains are all tax-free
• Resets: every 6 April; unused allowance is lost, not carried forward
• Each adult gets their own £20,000 - a couple can shelter £40,000

What the ISA allowance is

An ISA (Individual Savings Account) is a tax-free wrapper. In 2026/27 you can pay in up to £20,000 across your ISAs in a tax year, and any interest, dividends or capital gains earned inside are completely free of tax. The allowance resets each 6 April and cannot be carried forward, so any unused part is lost at the end of the tax year.

The main types of ISA

Project growth with the ISA calculator, and if you're saving for a first home, see the Lifetime ISA calculator.

Why ISAs matter more in 2026/27

Several tax-free allowances have shrunk: the dividend allowance is just £500, the capital gains allowance is £3,000, and higher savings rates mean the Personal Savings Allowance is easily breached. Money inside an ISA sidesteps all of these. Interest avoids the tax on savings interest, and investments avoid dividend tax and capital gains tax.

Real-life examples

Example 1 - a saver beating interest tax. Nadia, a higher-rate taxpayer, has £25,000 in savings. Outside an ISA, interest above her £500 allowance is taxed at 40%. Moving £20,000 into a cash ISA this year (and the rest next year) keeps that interest tax-free. Compare with the savings interest tax calculator.

Example 2 - an investor sheltering dividends and gains. Tom holds shares outside an ISA paying £2,000 of dividends and sitting on a £5,000 gain. Inside a stocks and shares ISA, both would be tax-free, avoiding the 2026/27 dividend rates and the £3,000 CGT allowance limit.

Example 3 - a couple doubling up. Each adult has a £20,000 allowance, so a couple can shelter £40,000 a year between them - useful for splitting larger savings to keep all the interest tax-free.

Who should prioritise it

• Savers whose interest is near or over their Personal Savings Allowance.
• Investors holding shares or funds outside a tax wrapper.
• First-time buyers, who can use a Lifetime ISA for the government bonus.

How to make the most of your allowance

• Use it before 5 April - the allowance does not roll over.
• Move taxable savings into a cash ISA if you are paying tax on interest.
• Each adult has their own £20,000, so couples can shelter up to £40,000 a year.
• Consider a stocks & shares ISA for long-term money, to shelter dividends and gains.

Common mistakes to avoid

Don't leave it to the last week of the tax year and risk missing the deadline. Don't withdraw and re-pay carelessly - with a non-flexible ISA, money you take out still counts against your allowance. And don't hold large taxable savings "just in case" when an ISA gives the same access with no tax on the interest.

Choosing the right ISA for your goal

The best ISA depends on your time horizon. For money you might need within a few years - an emergency fund, a near-term purchase - a cash ISA is usually right, because the value won't fall and the interest is tax-free. For money you can leave invested for five years or more, a stocks and shares ISA gives the chance of higher returns, with all growth and dividends free of tax, though the value can go down as well as up. For first-home savers under 40, a Lifetime ISA adds a 25% government bonus on up to £4,000 a year, though it comes with rules and a withdrawal penalty if used for anything other than a first home or retirement.

You can split your £20,000 across different ISA types in the same year - for example some in cash and some in stocks and shares - as long as the total stays within the allowance. This flexibility lets you match each pot to its purpose.

More real-life examples

Example 4 - Bed and ISA. Ravi holds shares outside any wrapper that pay dividends and have grown in value. By selling them and immediately rebuying inside a stocks and shares ISA - a process providers call "Bed and ISA" - he moves up to £20,000 a year into the tax-free wrapper, sheltering future dividends and gains. He needs to watch the capital gains tax on the sale itself, but doing it gradually across tax years keeps that within the CGT allowance.

Example 5 - a first-time buyer's bonus. Aisha, 28, saves £4,000 a year into a Lifetime ISA for her first home. The government adds a 25% bonus - £1,000 a year - on top, and the interest or growth is tax-free. Over several years the bonus alone can add thousands toward her deposit. See the Lifetime ISA calculator.

Example 6 - last-minute allowance use. In late March, Tom realises he has £8,000 of unused ISA allowance and £8,000 sitting in a taxable savings account generating taxable interest. By moving it into a cash ISA before 5 April, he uses the allowance before it resets and makes the interest tax-free from then on.

Timing and flexibility

Two practical points are worth knowing. First, the allowance is strictly use-it-or-lose-it: it resets every 6 April and cannot be carried forward, so unused allowance is gone for good at the tax-year end. Second, check whether your ISA is "flexible" - a flexible ISA lets you withdraw money and replace it within the same tax year without it counting again toward your £20,000, which is useful if you might need temporary access. Not all ISAs offer this, so confirm before relying on it. The ISA calculator helps you plan your contributions.

The rules on paying into ISAs

A few rules are worth understanding so you use your allowance correctly. You can pay into one of each type of ISA in a tax year and split your £20,000 across them however you like - for instance, £8,000 in a cash ISA and £12,000 in a stocks and shares ISA. The Lifetime ISA has its own sub-limit of £4,000 a year, which counts toward (not on top of) your overall £20,000. Money you transfer between existing ISAs does not use up new allowance, provided you use the official transfer process rather than withdrawing and re-depositing - withdrawing first can lose the tax-free status, so always ask the new provider to arrange the transfer.

It is also worth knowing that ISA limits apply per person, not per account, and that children can have Junior ISAs with their own separate allowance. For a family, that means parents and children each have tax-free room, which can add up to a substantial total across a household.

A worked example: the cost of not using your allowance

Picture two higher-rate taxpayers who each save £20,000 a year for five years at 4.5%. The one who uses a cash ISA pays no tax on any of the interest. The one using an ordinary account has only a £500 Personal Savings Allowance, so most of the growing interest is taxed at 40% year after year. Over five years, as the balance and the interest grow, the ISA saver ends up meaningfully ahead - purely from sheltering money they were going to save anyway. The same logic applies even more strongly to investments, where dividends and capital gains inside a stocks and shares ISA escape the £500 dividend allowance and the £3,000 CGT allowance entirely. Project the difference with the ISA calculator and savings interest tax calculator.

Making it a yearly habit

The single best way to benefit from ISAs is to use them consistently rather than perfectly. Set up a regular monthly payment into your ISA so you are not scrambling before 5 April, prioritise the wrapper if you are a higher-rate taxpayer or already paying tax on savings or investments, and review once a year whether the type of ISA still matches your goals. Because the allowance resets each year and cannot be carried forward, steady use captures far more tax-free growth over a lifetime than occasional large top-ups.

Key takeaways

• You can pay up to £20,000 across your ISAs in 2026/27 - all interest, dividends and gains are tax-free.
• The allowance resets every 6 April and cannot be carried forward.
• Cash ISAs suit short-term money; stocks and shares ISAs suit long-term investing; Lifetime ISAs add a 25% bonus.
• Each adult has their own £20,000, so a couple can shelter up to £40,000 a year.
• Use the official transfer process to move ISAs - never withdraw and re-deposit, which loses the tax-free status.
• ISAs matter more now that the dividend (£500) and capital gains (£3,000) allowances have been cut.

The bottom line

With other allowances cut, the £20,000 ISA is the most valuable tax shelter most people have. Use it each year, prioritise it if you're paying tax on savings or investments, and remember a couple can shelter £40,000. Read the official rules on GOV.UK.

General information only, not personal advice.