The best cash ISAs – December 2025

In brief:

Cash ISAs from less well-known banks and building societies are offering interest rates higher than the current rate of inflation. When MoneyWeek researched rates in December 2025, it found the best easy-access account allowing penalty-free withdrawals offered 4.49% interest. Savers who don’t need to access their cash can earn up to 4.3% interest by placing it in a one-year fixed-rate account, while two and three-year fixed-rate accounts offer up to 4.17% and 4.16% respectively.

The best cash ISAs are currently returning inflation-busting rates of up to 4.49%. For those who want to lock in their cash for a set time, fixed-rate cash ISAs are a good place to start.

Every adult in the UK gets a £20,000 tax-free Individual Savings Account (ISA) allowance each fiscal year. However, this is about to change from April 2027.

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In the Autumn Budget, Rachel Reeves announced that the limit for cash ISAs will be cut to £12,000 for under-65s.

While the overall £20,000 allowance isn't changing, savers will need to invest the remaining £8,000 into the UK stock market if they wish to grow their savings.

We round up the best cash ISAs on the market today.

The best easy access cash ISAs

Easy access cash ISAs do what they say on the tin, letting you access your savings without penalty. You can currently earn up to 4.49% with this type of ISA.

The best one-year fixed rate cash ISAs

If you’re happy to lock your cash away without any withdrawals for a year, then you're guaranteed returns of up to 4.3% until your fixed term ends.

The best two-year fixed rate cash ISAs

If you have savings you’re happy to lock away for at least two years, you’ll find rates on cash ISAs of up to 4.17%.

The best three-year fixed rate cash ISAs

What you need to know about the best cash ISAs

When choosing a cash ISA, there are two main factors to look out for: how long you are comfortable locking your cash up for and the interest rate.

• Easy access ISA accounts allow you to withdraw funds without incurring a penalty.
• Fixed-rate cash ISAs offer a fixed rate of return – usually higher the longer you are prepared to lock your money away. Note: if you withdraw money before the end of the term, then you are likely to be penalised, usually with a reduction in the rate of interest.

Generally speaking, the longer you leave the money untouched, the more interest you can earn. Many ISAs are classed as ‘flexible’, meaning you can replace any funds you withdraw in the same tax year without affecting your annual ISA allowance – which is currently £20,000.

We have an ISA guide to help you learn everything you need to know about how they work, how much you can pay in, what investments you can hold, and how to transfer one.