Make the Most of Tax-Free Returns

The word tax written on wooden dice lying on top of stacks of coins in a studio shot.

ISAs (Individual Savings Accounts) help you grow your money without paying tax on the returns. You can save or invest up to £20,000 each tax year. Any interest, income or profit you earn within this limit is tax-free. ISAs are simple to use and can help you save more, invest smarter and plan for the future.

What this guide covers:

How ISAs work. Including tax-free interest, income and capital gains
Key dates and limits. Like £20,000 annual allowance and ISA tax year
Smart saving tips. Such as using flexible ISAs and contributing early
Planning ahead. Avoid losing any tax-free benefits and what happens to ISAs when you die

Is interest on an ISA tax-free?

Any interest you earn from an ISA is tax-free. This applies to all types of ISAs.

With a Cash ISA, you don’t pay tax on the interest from your savings. With a Stocks and Shares ISA, you don’t pay tax on income or capital gains from your investments.

You can save up to £20,000 across your ISAs each tax year. You won’t pay tax on the interest you earn within this limit.

Want to know more? Visit the UK Government website to learn how ISAs work.

When does the ISA tax year start and end?

The UK ISA tax year runs from 6 April to 5 Aprill the following year, and these dates never change.

The time between February and April is commonly referred as 'ISA season'. During this time, some providers may offer better interest rates to attract savers.

Putting money into your ISA early in the year can also help it grow more. That's because your savings have more time to earn interest - and benefit from compounding.

How does the cash ISA tax year work?

Between 6 April and 5 April, you can save up to £20,000 in a Cash ISA. Your interest depends on the rate you choose: fixed rates offer certainty, while variable rates can rise or fall over time. Depending on your provider, interest may be paid monthly or once a year.

At the end of the tax year, your ISA allowance resets unused allowance can't be carried over, so it's use it or lose It. Making the most of your allowance and picking the right rate can significantly boost your savings.

What happens to a cash ISA at the end of a tax year?

Any money you add to your Cash ISA after 5 April will count towards the new tax year’s allowance. You can still earn tax-free interest on deposits up to £20,000 in the new year.

The end of the tax year is a good time to review your ISA. You might want to switch to a new provider if they offer a better interest rate. But you don’t have to wait – you can transfer your Cash ISA at any time.

Can you transfer an ISA in the same tax year?

You can transfer an ISA during the same tax year, but it must be done through the official ISA transfer process. This is important because it protects your tax-free status and ensures you don’t accidentally use up more of your £20,000 annual allowance.

If you withdraw money and open a new ISA, the deposit may count as a new contribution, which could lead to you going over your allowance. Always ask your provider to arrange a formal transfer to keep your ISA benefits intact.

How much can you save tax-free in an ISA?

Each tax year, you can save up to £20,000 in ISAs. You can put all of it into one ISA or split it across different types.

Example: You could save £12,000 in a Cash ISA and £8,000 in a Stocks and Shares ISA in the same tax year.

It’s worth keeping track of your deposits if you own multiple ISAs, so you know how much tax-free allowance you have left.

Do you pay Capital Gains Tax on ISAs or share save schemes?

For any profits you make on investments held in an ISA (like a Stocks & Shares ISA), you don’t pay Capital Gains Tax (CGT).

For share save schemes like Save As You Earn (SAYE), you can transfer shares into your ISA and avoid paying CGT if you do it within 90 days of the scheme ending. All shares you transfer into your ISA count towards your ISA allowance.

Tips to make the most of your ISA allowance

Want to get the most from your ISA each year? Here are a few simple tips.

Split allowance between Cash and Stocks & Shares ISAs

You don’t have to choose just one type of ISA. You can split your allowance between a Cash ISA and a Stocks & Shares ISA.

A Cash ISA is lower risk and is sometimes considered good for short term savings goals.
A Stocks & Shares ISA carries more risk but may offer higher returns over time. Capital at risk.

This mix can help balance safety and risk as you look for higher growth potential.

Use flexible ISAs if needed

Some lenders offer flexible ISAs. These let you take money out and put it back in without losing your allowance.

Example: If you withdraw £5,000 and put it back in the same tax year, it still counts within your £20,000 limit. With a regular ISA, the second deposit would count as new money and could push you over the limit.

Maximise contributions early in the tax year

The earlier you put money into your ISA, the more time it has to grow. Adding funds at the start of the tax year helps you make the most of compound growth – where you earn interest on your interest.

This can help your savings grow faster over time.

Make ISAs work in retirement planning

ISAs can play a useful role in retirement planning, especially when used alongside pensions. By carefully choosing when to withdraw from each, you may be able to manage your Income Tax more effectively. For example, taking money from an ISA instead of a pension in some years could help you stay within a lower tax band.

ISAs can also be part of your inheritance planning. However, it’s important to know that ISAs are not automatically free from Inheritance Tax. To learn more, see our guide to Inheritance Tax.

Can you lose the tax benefits on an ISA?

There are a few ways you could lose the tax-free benefits of an ISA:

Withdrawals. If you take money out, it loses its tax-free status. Only money inside the ISA is protected from tax.
Going over the limit. If you deposit more than £20,000 in a tax year, the extra amount may be taxed.
Not using your full allowance. If you don’t use all your allowance by 5 April, you can’t carry it over to the next year.

What happens to your ISA if you die?

If you die, your ISA savings and investments go to the people named in your will. But first, your estate must be settled.

While that’s happening, your ISA becomes a ‘continuing ISA’. It keeps its tax-free status, but no more money can be added.

Once your estate is settled, the money in your ISA is paid to your beneficiaries. Your ISA may also end if your executors choose to close it.

If neither happens, the account will close automatically 3 years and 1 day after your death.

A desk with a computer, a piggy bank and some paperwork with the word Individual Savings Account printed at the top

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Make the most of tax-free returns