Best Cash ISAs – Who has the best interest rate for you?

Antonia says

This is a remarkably good rate. Second only to Moneybox when the 90-day introductory rate is included. Even once it drops down to the basic rate, it is still excellent, and far higher than Moneybox’s 4.20% AER basic rate.

You also don’t need as large a deposit for this account – just £1 vs Moneybox’s £500.

It’s a flexible ISA which is great news if you might want to withdraw money during the tax year and don’t want to lose any of your allowance. Plus, you can access your money with no withdrawal limit – no matter how many times you withdraw money, CMC won’t reduce your interest rate.

Something you may want to be aware of, however, is that CMC Invest, like Trading 212 and Plum, may put your deposits into Qualifying Money Market Funds instead of bank vaults. If a QMMF goes down in value, this may affect the value of your cash. The risk is very low, however. Platforms choose this option as it allows them to skim a layer of interest from the returns that can be gained on investments.

Fees

No fees.

Antonia says

Tembo is an award-winning digital mortgage & savings platform. It was voted the UK’s Best Mortgage Broker by its customers at the British Bank Awards in 2022, 2023 and 2024. And in 2024 it expanded to also offering savings products with some excellent rates of interest.

There’s a market leading Lifetime ISAs (Individual Savings Accounts) (LISAs) are designed to help you save for your first home or retirement and come with an automatic 25% government bonus on all contributions up to the value of £4,000. There are stocks and shares LISAs – where you invest your savings – and cash LISAs – where you earn interest on your savings. You must be between 18 and 40 to open a LISA and all income, capital gains and interest earned within LISAs is tax-free, although these funds can only be used to purchase your first home or for retirement. Ensure you are familiar with the rules surrounding this account before utilising itLifetime ISA and this Cash ISA which also has one of the highest rates of interest offered by any platform, just slightly pipped into second place by CMC Invest. There are no penalties if you need to get your hands on any of that cash, no limits on the number of times you can withdraw without being penalised with a lesser rate, and no fees. It’s also quick and easy to make withdrawals with requests made before 2pm being processed that same working day, and requests after the cut-off available the following working day.

So it’s a great option with an exceptionally good rate of interest.

A couple of points to note, though: Firstly, the Tembo Cash ISA is not a flexible ISA. This means that if you withdraw funds and later redeposit them within the same tax year, the redeposited amount will count twice towards your annual ISA allowance. Secondly, as with all products in this list, it’s a variable rate of interest, which means it can be adjusted up or down if the Bank of England changes the base rate of interest.

Fees

No fees.

Antonia says

Trading 212 already appears on many of our ‘Best of’ lists at Investing Insiders. So we were already fans of their exceptional value and uncomplicated interface for investors. But now they have rolled out one of the highest rates of interest available on any UK cash ISA (4.5% APY), we’re big cheerleaders for their savings options too.

Moneybox and Plum have significantly higher rates, but they both only outperform Trading 212 if you consider their bonus rates, which are only applied for 3 months. Once those drop away, Trading 212 is a very good rate, although not as high as CMC Invest’s and Tembo’s.

Trading 212’s Cash ISA is also a If an ISA is flexible, you’re able to withdraw money and pay it back in, without it counting twice within your annual ISA allowance. It must be repaid within the same tax year it’s withdrawn to be eligible, however.flexible ISA, which many on our list are not, and there are no penalties for accessing you cash at any time, as many times as you want. That makes this a great option if you feel you might need the cash you’re saving. If you’re starting small then T212’s £1 minimum deposit is also more accessible than Moneybag’s £500 minimum.

One thing to note – Trading 212, like CMC Invest and Plum, may put your deposits into Qualifying Money Market Funds instead of bank vaults. If a QMMF goes down in value, this may affect the value of your cash. The risk is very low, however.

Fees

No fees, even to access T212’s investment accounts.

Antonia says

We talk about Moneybox a lot at Investing Insiders as our analysis has shown that they are a great place for beginners to start investing.

They now also take the crown for having the highest interest rate on a cash ISA in the UK market, currently an exceptional 4.20% AER + a 1.51% boost (5.71% total) for new customers for 3 months.

The downsides are, however, you need a minimum of £500 to get started, you only get 3 withdrawals before you’ll be penalised with a lower rate, and the bonus now only lasts for 3 months, not the 12 months that was previously offered. Once the bonus drops out after 3 months, you’ll be left with a rate that isn’t as high as you could get at Trading 212.

Don’t forget, though, you’re free to transfer your Cash ISA to a new provider as many times as you want. So if you want a quick boost, this is a fantastic option. Just remember to always use the official transfer process, and aways let the new provider initiate the transfer — don’t withdraw the money yourself, or you’ll lose the ISA tax benefits. There are no exit fees on the cash ISAs we’ve featured on this page, but some providers may apply them.

Fees

Zero fees associated with the cash ISA
£1 subscription fee and 0.45% platform fee for investing

Antonia says

This is a fantastic rate if you’re a new customer and can therefore get the bonus rate. It’ll only last for 12 months however, but shopping around, and regularly switching accounts is a good habit to get into when there’s a rates war going on!

I’ve had an account with Plum since 2021 and can confirm that it is a very convenient, helpful way to save money. If you choose to use the smart features, the algorithm analyses your income and expenditure in order to put aside small amounts that you can afford, and will barely notice.

There are penalties for accessing your cash to watch out for here, and you won’t get the same top rate if you’re transferring in an existing cash ISA, however, so it’s best suited to those who are setting up a first cash ISA and who won’t need to make regular withdrawals.

Fees

Zero to pay for the cash ISA.

Antonia says

New customers can get a boosted rate for 180 days that pays 4.89% AER in total. After that (and for existing customers) it’s 4.32%. 4.89% is an exceptionally good rate right now, and makes Chip the second highest paying Cash ISA in our list.

Even without the boost, it’s still a strong rate but it is a tracker rate, which means it tracks at 0.26% below the Bank of England base rate. While this means that if the rate moves up, Chip account holders stand to gain, it also means the rate could go down at any time.

You can access the Chip cash ISA for free; however, a lot of their features come with a fee including autosaves which will cost 45p per save. These are free with Plum so that’s a consideration.

Fees

Zero fees to use the cash ISA but you will pay to use the automated savings tools.

Antonia says

Marcus might not be a name you’re familiar with but as a Goldman Sachs brand, you’re getting peace of mind that this is a financial services giant.

Interest is calculated daily and paid monthly, but you won’t be able to transfer in any existing ISAs you have and this top rate only applies to new customers, and only lasts for 12 months. After that (or if you’re an existing customer), the rate is 3.79% AER.

It also isn’t a flexible ISA, which whatever you take out can’t be replaced within your tax-free allowance. You’ll also lose the tax-free benefit on any future interest earned on that withdrawn amount.

Fees

No fees to use this cash ISA.