ISA guide: everything you need to know for the 2024/25 tax year

In our ISA guide, we explain everything you need to know about ISAs: how they work, how much you can pay in, what investments you can hold, and how to transfer one.

ISA guide: a 3D abstract background of piggy banks
(Image credit: Eugene Mymrin)

Whether it’s saving for your retirement, children, a first home, or simply for a rainy day, ISAs (individual savings accounts) are a tax-efficient way to help you achieve your financial goals. We look at how they work in our ISA guide.

There are six types: cash ISAs, stocks and shares, junior ISAs, innovative finance, lifetime, and help to buy.

While ISAs are a great way to protect your money from the taxman - and some even come with free cash from the government to encourage you to save - there are a few rules to be aware of.

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One of the main ones is the annual allowance. You can currently save a total of £20,000 across all your adult ISAs each tax year. So, you could save £5,000 in a cash ISA and £15,000 in a stocks and shares ISA. Note that this is a maximum threshold, so you could also just save £2,000 in a lifetime ISA, and that’s it for the tax year.

Junior ISAs have a separate £9,000 annual allowance, and you also need to be mindful of additional limits on lifetime ISAs and help to buy ISAs. Bear in mind these allowances are all “use it or lose it” - any unused allowances will not roll over into the tax year.

Plus, with the recent ISA changes kicked in this month, it's a good time to scrub up on how to make the most of your £20,000 allowance.

We explain how the limits work, and run through everything else you need to know about ISAs, from what sort of investments you can hold to how to transfer an ISA.

Cash ISAs

A cash ISA is essentially a savings account where you pay in money and earn interest on your savings. The key difference is that unlike a conventional savings account, a cash ISA is tax-free, so regardless of how much you earn, you won’t pay a penny in tax.

There are several different cash ISAs to choose from. An easy-access ISA is a useful home for your emergency savings pot, as these allow you to withdraw money when you need it without incurring a penalty - although some may restrict the number of withdrawals so do check.

Fixed-term ISAs pay a certain interest rate over a set period of time, typically one to five years, much like a savings bond. They tend to offer higher rates than easy-access ISAs, but in exchange, you have to lock your money up.

Flexible cash ISAs allow you to take money out and replace it during the same tax year, without that amount being deducted from your allowance. For example, you could pay in £20,000, then withdraw £5,000, and a flexible ISA would allow you to pay the £5,000 back in during the same tax year. Not all cash ISAs offer this “flexible” status, so check with the bank or building society.

As previously noted, the total you can pay into adult ISAs per tax year is £20,000. So, you could contribute a maximum of £20,000 to a cash ISA. Or you could, say, contribute £10,000 to a cash ISA, £7,000 to a stocks and shares ISA, and £3,000 to a lifetime ISA.

Another rule to be aware of that has only just come into effect is you can hold multiple ISA subscriptions within the £20,000 allowance. Before 6 April, you could only hold one cash ISA and one stocks and shares ISA per tax year. Now, you can hold multiple of the same type of ISA within the same year.

In terms of transferring an ISA, you’re free to move a cash ISA to one that pays a better interest rate without affecting this year's allowance - as long as you fill out the correct transfer forms. Contact the ISA provider you want to move to and complete the transfer form. If you withdraw the money without doing this, you will not be able to reinvest that part of your tax-free allowance again. If you want to move money you’ve invested in an ISA during the current year, you must transfer all of it.

Cash ISA transfers should take no longer than 15 working days, according to government rules. You’re also free to move to a different type of ISA, such as from cash to stocks and shares, or say, from innovative finance to cash.

Stocks and shares ISAs

Stocks and shares ISAs, also known as investment ISAs, allow savers to invest in a broad range of assets. Any investment gains you make will not be subject to capital gains tax, income tax or dividend tax. The only tax you may have to pay is stamp duty when buying shares.

The best way to think of a stocks and shares ISA is an investment account with a tax-efficient wrapper around it. Like a general investment account, you can buy everything from shares to bonds to property in the form of real-estate investment trusts (Reits), plus open-ended funds (Oeics) and exchange-traded funds (ETFs).

Some stocks and shares ISAs are ready-made portfolios (think MoneyBox, Wealthify and Nutmeg) while there are also lots of DIY versions (providers include Hargreaves Lansdown, AJ Bell, Charles Stanley Direct and many others), where you can pick your own funds, bonds and shares.

As with any investment account, ensure you check the fees levied by the ISA provider. There could be an annual fee for a stocks and shares ISA, fees to trade investments, and possibly an exit charge.

To move a stocks and shares ISA, ask your new provider for a transfer form. Transfers usually take longer than those for a cash ISA; the government says providers should complete them within 30 calendar days.

Lifetime ISAs

Lifetime ISAs are the most generous member of the ISA family, with a government bonus of up to £32,000 on offer. Launched in April 2017, they have the dual aim of helping those under 40 get onto the property ladder or save for retirement.

To open one, you must be aged between 18 and 39. You can contribute up to £4,000 each tax year until you’re 50. The money you pay in counts towards your £20,000 ISA limit. You can hold cash or stocks and shares in a lifetime ISA, or a combination of both.

The best bit about lifetime ISAs is you get free cash from the government. Savers get a juicy 25% bonus worth up to £1,000 every tax year, depending on your contribution. For example, if you pay £2,000 into your lifetime ISA in a tax year, you’ll receive a £500 top-up.

You can only access the money at 60 or over, or to buy your first property up to the value of £450,000.

While the government bonus is a great incentive to open a lifetime ISA, bear in mind that if you use it for anything other than your first house or for a pension, you’ll be hit with a 25% withdrawal charge, which means you could end up with less than you put in.

Junior ISAs

If you have children or grandchildren, you can save into a junior ISA for them.

These can be the cash or stocks and shares variety. The account has to be opened by a parent or guardian, but once it’s set up, anyone can add money to it up to £9,000 per tax year. As with adult ISAs, any investment gains or interest earned is totally tax-free.

The child cannot touch the money until they are 18. As soon as they reach their 18th birthday, they can spend it - or save or invest it - as they choose. This means alongside the cash you deposit into their account, try and also deposit good financial habits into their brains by teaching them about money.

If your child has a child trust fund (CTF) - and those born before January 2011 will have one - consider moving it into a junior ISA. Simply request a transfer form from the junior ISA provider. Cash junior ISAs typically have higher interest rates than CTFs, while stocks and shares junior ISAs generally have lower fees than the CTF versions.

Innovative Finance ISAs

Innovative Finance ISAs (IF ISAs) were introduced in 2016 to allow people to invest some or all of their £20,000 annual allowance in peer-to-peer lending and enjoy tax-free returns.

This involves lending your money directly to businesses and individuals without a middleman, such as a bank, in return for interest. Providers include Triodos Bank and EasyMoney.

These are considered the most risky ISA option. Because each ISA provider tends to specialise in a particular niche – small businesses, consumers or property developers, for example – and you can only contribute to a single IF ISA in any one tax year, it is difficult to diversify across different sectors.

Help to Buy ISAs

It’s no longer possible to open a help to buy ISA, as they have been replaced by lifetime ISAs. However, if you already have one, you can continue paying into it until November 2029.

You can contribute up to £200 each month. The government then tops up your savings by 25% (up to £3,000) when you buy your first home. You can claim the bonus until November 2030. The home you buy must be priced at £250,000 or less (£450,000 or less in London), be the only property you own and where you intend to live.

Lifetime ISAs are more flexible as the property maximum is £450,000 for the whole of the UK, you can use it as a retirement nest egg if you don’t end up buying a home, plus the annual allowance is higher. So you may wish to consider transferring a help to buy ISA into a lifetime ISA.

Ruth Emery
Contributing editor

Ruth is passionate about helping people feel more confident about their finances. She was previously editor of Times Money Mentor, and prior to that was deputy Money editor at The Sunday Times. 

A multi-award winning journalist, Ruth started her career on a pensions magazine at the FT Group, and has also worked at Money Observer and Money Advice Service. 

Outside of work, she is a mum to two young children, a magistrate and an NHS volunteer.