Best Cash ISAs UK August 2026: Compare Top Rates Up to 4.87%
Cash ISAs let you earn tax-free interest on your savings, making them one of the most straightforward ways to grow your money in the UK. Headline rates currently reach up to 4.87% AER, although the highest figure comes with conditions, so it is worth comparing the terms as closely as the rate.
We have compared the leading Cash ISA providers by headline first-year rate. eToro, through its partnership with Moneyfarm, shows the highest headline rate at 4.87% AER variable for eligible new Moneyfarm customers. That figure is not a simple ongoing rate. It combines a standard introductory rate of 3.87% AER variable with a 1 percentage point boost paid after the first 12 months, and it requires a £500 deposit or a £5,000 ISA transfer to open, a balance of at least £500 and no more than three withdrawals during the first year. The standard rate is 3.57% AER variable after 12 months, and it also applies if you exceed three withdrawals in the first year.
Plum follows at 4.40% AER for the first year, which includes a 1.86 percentage point bonus before the underlying rate of 2.54% takes over. If you would rather not track opening minimums, withdrawal limits and anniversary dates, compare the ongoing rates as well as the headline figures.
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Cash ISA Providers Ranked by Headline First-Year Rate
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Provider Overview
1. eToro Cash ISA: 4.87% AER for the first year
eToro shows the highest headline rate in this comparison at 4.87% AER variable, delivered through a partnership with Moneyfarm. The figure is conditional and applies to eligible new Moneyfarm customers only. It combines a standard introductory rate of 3.87% AER variable with a 1 percentage point boost paid after the first 12 months.
To qualify you need to open with a £500 deposit or a £5,000 ISA transfer, hold at least £500 and make no more than three withdrawals during the first 12 months. The boost is paid after the first anniversary, so closing or transferring the ISA before then means you do not receive it. The standard rate of 3.57% AER variable applies after 12 months, and it also applies if you make more than three withdrawals during the first year. The offer opened on 29 July 2026 and can be withdrawn at Moneyfarm's discretion.
The Cash ISA invests in a qualifying money market fund. It is not a bank deposit. Eligible client assets may be covered by FSCS investment protection up to £85,000 if Moneyfarm fails, and that protection does not cover investment losses caused by market performance.
eToro also removed the fees from its DIY Stocks and Shares ISA on 29 July 2026. That account carries 0% dealing commission and no annual custody fee, with a 0.70% foreign exchange charge on non-GBP assets and a choice of UK, US and European shares, ETFs, bonds and mutual funds. The managed Moneyfarm ISA is a separate product with its own charges.
Best for: Savers who can meet the opening minimum and the three-withdrawal limit and who expect to keep the ISA open for at least 12 months.
Read our full eToro Cash ISA review or learn about the eToro UK bonus.
eToro is a multi-asset investment platform. The value of your investments may go up or down. Your capital is at risk. 51% of retail investor accounts lose money when trading CFDs with this provider.
2. Plum Cash ISA: 4.40% AER
Plum offers 4.40% AER on its Cash ISA. The headline rate includes a 1.86% bonus for the first 12 months. The underlying variable rate is 2.54% after the bonus period. ISA transfers receive 3.75% AER, including a 1.21% first-year bonus. Plum is a money management app that also offers budgeting tools and investment options.
Best for: Savers who want a high first-year rate alongside automated budgeting tools.
3. Atom Bank Cash ISA: 4.25% AER
Atom Bank offers 4.25% AER on its easy access Cash ISA. As a digital-only bank, Atom Bank provides a straightforward savings experience through its mobile app with no bonus periods or introductory rate changes.
Best for: Savers who want a competitive flat rate from an established digital bank.
4. XTB Cash ISA: 4.00% AER
XTB offers 4.00% AER variable on its Cash ISA with no bonus period and no withdrawal limits. The Cash ISA is flexible, meaning you can withdraw and replace funds within the same tax year without affecting your annual ISA allowance. Transfers from other ISA providers are also supported without losing your tax-free status.
New clients can also claim a free share from a choice of UK-listed companies including Rolls-Royce, Barclays, Tesco, BP, and Glencore. Availability is limited.
Best for: Savers who want a flat-rate ISA from a regulated investment platform with a free share bonus on top.
Read our full XTB Cash ISA review.
Capital at risk. Limited free stock availability. New clients only. T&Cs apply.
5. Moneybox Cash ISA: 4.00% AER
Moneybox offers 4.00% AER on its Cash ISA. The headline rate includes a 0.55% bonus for the first 12 months, with the rate reverting to a lower underlying rate after the bonus period ends. Moneybox is known for its round-up savings feature and offers Lifetime ISAs and investment accounts alongside the Cash ISA.
Best for: Savers who use Moneybox for other products or want automated round-up savings features.
6. Lightyear Cash ISA: 3.75% AER
Lightyear offers 3.75% AER on its Cash ISA, tracking the Bank of England base rate. Lightyear is an investment app that offers commission-free ETF trading alongside its savings products. New customers can get up to £100 in free US shares. Read our full Lightyear review.
Best for: Savers who want a transparent BoE-tracking rate combined with investing.
7. Trading 212 Cash ISA: 3.60% AER
Trading 212 offers 3.60% AER on its Cash ISA, tracking the Bank of England base rate minus 0.15%. The account is fully flexible with no withdrawal limits. New customers can get free shares worth up to £100 with promo code.
Read our full Trading 212 review or check out our Trading 212 promo code article.
Best for: Savers who want flexibility and an established investment platform.
8. Monzo Cash ISA: 2.75% AER
Monzo offers 3.25% AER on its Cash ISA for customers on Monzo Plus, Premium, Perks, or Max plans. Customers on the free tier currently earn 2.75% AER. Monzo is one of the most popular digital banks in the UK, making it easy to manage your ISA alongside your everyday banking.
Best for: Existing Monzo customers on a paid plan who want to keep everything in one app.
Related: High-Yield Savings Accounts
If you have already used your ISA allowance or want additional savings options, check out our best high-yield savings accounts UK comparison.
What to Consider When Choosing a Cash ISA
Interest Rate
Higher is better, but check whether the rate includes a bonus that expires after 12 months. Some providers offer stable rates without bonuses, while others front-load introductory rates that later drop significantly.
FSCS Protection
Traditional Cash ISAs are bank deposits and fall under FSCS deposit protection, currently up to £120,000 per person per institution. QMMF-based Cash ISAs, including the eToro and Moneyfarm product, are not bank deposits. They invest in a qualifying money market fund and fall under FSCS investment protection, which caps at £85,000 and applies if the firm fails. Investment protection does not cover losses caused by market performance, so the two structures are not protected in the same way.
Flexibility
A flexible ISA lets you withdraw and replace money within the same tax year without using up additional allowance. Most fintech Cash ISAs are flexible, but check before opening.
Proposed Cash ISA Limit Changes from April 2027
The £20,000 ISA allowance for the 2026/27 tax year applies until 5 April 2027. The overall ISA allowance is set to stay at £20,000 from 6 April 2027. What would change under the proposal is how much of that allowance can go into cash: Cash ISA subscriptions would be capped at £12,000 a year for savers under 65, with the balance of the £20,000 still available for stocks and shares and other qualifying ISAs. Savers aged 65 and over would keep a £20,000 Cash ISA subscription limit.
This is a proposal rather than a settled rule. It depends on the 2026 draft regulations completing the legislative process, so treat the £12,000 cash cap as provisional and check the final legislation before planning your 2027/28 contributions.
Frequently Asked Questions
What is a Cash ISA?
A Cash ISA is a tax-free savings account. You can deposit up to £20,000 per tax year across all ISA types, and any interest earned is free from income tax. This makes Cash ISAs more efficient than regular savings accounts, especially for higher earners.
Can I have multiple Cash ISAs?
Yes, since April 2024 you can open and pay into multiple Cash ISAs in the same tax year, as long as your total contributions do not exceed the £20,000 annual allowance.
Are Cash ISAs worth it?
For most UK savers, yes. Headline rates in this comparison currently reach up to 4.87% AER on a conditional first-year offer, with several accounts around 4.00% to 4.40% AER, and all returns are tax-free. They are particularly valuable if you have used your Personal Savings Allowance or pay a higher rate of income tax.
What is the difference between a Cash ISA and a Stocks & Shares ISA?
A Cash ISA holds your money in a savings-style account earning interest. A Stocks & Shares ISA invests your money in assets like shares and funds, with potential for higher returns but also risk of loss. Both offer tax-free growth.
Can I transfer my existing Cash ISA to a new provider?
Yes, you can transfer existing ISA funds to a new provider. However, some providers only pay their best rates on new deposits, not on transferred funds. Always check the terms before transferring.
How safe is my money in a Cash ISA?
It depends on how the account holds your money. Traditional Cash ISAs are bank deposits protected by the FSCS up to £120,000 per person per institution. QMMF-based Cash ISAs, such as the eToro and Moneyfarm product, invest in a qualifying money market fund instead. Eligible client assets may be covered by FSCS investment protection up to £85,000 if the firm fails, and that protection does not cover investment losses caused by market performance.
Kai is an investor who helps people choose the right broker and invest with confidence. He founded MatchMyBroker, a broker-comparison site for a global audience, and EU Investing Hub, his European-focused investing site. He also runs the Smart Money with Kai YouTube channel, where he breaks down investing, brokers and personal finance.
