Best Cash ISAs UK 2026: Compare Top Rates Up to 4.31%

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. With rates currently reaching up to 4.31%, now is a good time to compare your options.

We have compared the leading Cash ISA providers based on their interest rates. Plum currently leads the market with the highest standard rate at 4.31% AER.

Cash ISA Providers Ranked by Rate

Provider Overview

1. Plum Cash ISA: 4.31% AER

Plum offers 4.31% AER on its Cash ISA, the highest standard rate currently available in the UK. The headline rate includes a 1.77% bonus for the first 12 months, after which the rate reverts to the standard variable rate. Plum is a money management app that also offers budgeting tools and investment options.

Best for: Savers who want the highest available rate alongside automated budgeting tools.

2. 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.

3. XTB Cash ISA: 4.00% AER

XTB offers 4.00% AER 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.

4. 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.

5. eToro Cash ISA: 3.82% AER

eToro offers 3.82% AER variable on its Cash ISA, delivered through a partnership with Moneyfarm. The Cash ISA uses Qualifying Money Market Funds (QMMFs) rather than traditional cash deposits, which means FSCS protection is capped at £85,000 (investment protection) rather than the £120,000 available for standard cash deposits.

Best for: Existing eToro users who want a tax-free savings option alongside their investing account.

Read our full eToro Cash ISA review or learn about the eToro UK bonus.

6. IG Cash ISA: 3.75% AER

IG offers 3.75% AER on its Cash ISA. IG is one of the largest trading platforms in the UK and offers a range of investment products. New customers can get up to £3,000 cashback when transferring investments from another broker.

Best for: Experienced investors who want savings alongside trading.

Read more about the IG transfer cashback offer.

7. 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.

8. 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.

9. Chip Cash ISA: 3.55% AER

Chip offers 3.55% AER on its standard Cash ISA, tracking the Bank of England base rate. Chip also offers a higher 12-month introductory tier for new customers. The mobile-only platform also provides a stocks and shares ISA for those who want to invest.

Best for: Savers who want a simple mobile experience with automated savings.

10. Monzo Cash ISA: 3.25% 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 offer FSCS protection up to £120,000 per person per institution. QMMF-based ISAs (like eToro) fall under investment protection, which caps at £85,000. Both are safe, but the limits differ.

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.

ISA Allowance Changes Coming in 2027

The current £20,000 ISA allowance applies until 5 April 2026. From April 2027, the allowance will drop to £12,000 for most people, with those aged 65 and over retaining the £20,000 limit.

This makes it worth maximising your ISA contributions while the higher limit is still available.

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. Cash ISAs offer competitive interest rates (currently up to 4.31%) 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?

Traditional Cash ISAs are protected by the FSCS up to £120,000 per person per institution. QMMF-based Cash ISAs (like eToro) are covered by FSCS investment protection up to £85,000. Both provide strong protection for UK savers.

Risk Disclaimer: Interest rates shown are correct as of May 2026 and may change. Variable rates are subject to change without notice. Tax treatment depends on individual circumstances and may change in the future. For QMMF-based Cash ISAs, the value of investments can go down as well as up and you may get back less than you invest.