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Best cash Isas 2025
Discover the top easy-access and fixed cash Isa rates and the best Isa providers
Cash Isa rates boomed over the last couple of years thanks to 14 consecutive increases in the Bank of England base rate.
Unfortunately for savers, the base rate has since started to drop, meaning that rates are no longer quite as high as they were a few months ago. But 64% of cash Isas still pay above May's rate of inflation (3.4%). This means you should consider transferring your savings if your account isn't working hard enough.
Here, we reveal the cash Isas paying the highest interest across instant-access and fixed-rate deals as well as the best cash Isa providers, so you can decide on the right place to keep your money.
The best cash Isa rates in July 2025
Our experts regularly scour the market for the best rates so you don't have to. Here's what you can currently get, based on how long you're willing to lock your cash up for.
The top-rate instant-access accounts are based on an investment of £1,000, while for fixed-rate accounts it's £5,000.
Some providers offer a choice of how often interest is paid. Where this applies, we have listed all the options available in the 'Interest paid' column of each table.
The information in this article is for information purposes only and does not constitute advice. Please refer to the terms and conditions of the savings account provider before committing to any financial products. Please note that minimum and maximum deposit amounts vary, even across products with the same rate, so check the full details before you opt for a new account.
| Instant access | Tembo Money | 4.64% | £10 | Mobile app | Monthly |
| One-year fixed rate | Castle Trust Bank | 4.31% | £1,000 | Internet, mobile app | On maturity |
| Two-year fixed rate | Marsden Building Society | 4.30% | £5,000 | Internet | Yearly |
| Three-year fixed rate | United Trust Bank | 4.25% | £5,000 | Internet | Anniversary |
| Four-year fixed rate | UBL UK | 4% | £2,000 | Branch, internet, mobile app, postal | Monthly, quarterly, anniversary, on maturity |
| Five-year fixed rate | Castle Trust Bank | 4.24% | £1,000 | Internet, mobile app | On maturity |
Table notes: rates sourced from Moneyfacts on 7 July 2025. No providers in the table had a sample size large enough for us to generate a Provider customer score
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Compare and chooseBest instant-access cash Isa rates
Tembo Money | 4.64% | £10 | Mobile app | Monthly |
Trading 212 | 4.5% | £1 | Internet, mobile app | Monthly |
Table notes: rates sourced from Moneyfacts on 7 July 2025 and based on a balance of £1,000. No providers in the table had a sample size large enough for us to generate a Provider customer score
Best 1-year fixed-rate cash Isa rates
Castle Trust Bank | 4.31% | £1,000 | Internet, mobile app | On maturity |
Hodge Bank | 4.3% | £1,000 | Internet | Monthly, on maturity |
Vanquis Bank | 4.3% | £1,000 | Internet | Monthly, anniversary |
Table notes: rates sourced from Moneyfacts on 7 July 2025 and based on a balance of £5,000. No providers in the table had a sample size large enough for us to generate a Provider customer score
Best 2-year fixed-rate cash Isa rates
Marsden Building Society | 4.30% | £5,000 | Internet | Yearly |
United Trust Bank | 4.25% | £5,000 | Internet | Anniversary |
Table notes: rates sourced from Moneyfacts on 7 July 2025 and based on a balance of £5,000. No providers in the table had a sample size large enough for us to generate a Provider customer score
Best 3-year fixed-rate cash Isa rates
United Trust Bank | 4.25% | £5,000 | Internet | Anniversary |
UBL UK | 4.22% | £2,000 | Branch, internet, mobile app, postal | Monthly, quarterly, anniversary, on maturity |
Table notes: rates sourced from Moneyfacts on 7 July 2025 and based on a balance of £5,000. No providers in the table had a sample size large enough for us to generate a Provider customer score.
Best 4-year fixed-rate cash Isa rates
UBL UK | 4% | n/a | £2,000 | Branch, internet, mobile app, postal | Monthly, quarterly, anniversary, on maturity |
United Trust Bank | 4% | n/a | £5,000 | Internet | Anniversary |
RECOMMENDED PROVIDER Zopa | 3.8% | 77% | £1 | Mobile app | Monthly |
Table notes: rates sourced from Moneyfacts on 7 July 2025 and based on a balance of £5,000. Provider customer score is based on savers' overall satisfaction with the brand and how likely they are to recommend it to others. n/a means sample size was too small for us to generate a provider score.
Best 5-year fixed-rate cash Isa rates
Castle Trust Bank | 4.24% | £1,000 | Internet, mobile app | On maturity |
Nottingham Building Society | 4.23% | £500 | Internet, mobile app | Yearly |
Table notes: rates sourced from Moneyfacts on 7 July 2025 and based on a balance of £5,000. No providers in the table had a sample size large enough for us to generate a Provider customer score.
The best cash Isa providers
We know that customer service is an important factor for many people when choosing an Isa. But how do you find a bank or building society that combines great rates with top-notch customer service?
We've asked thousands of savers to rate their bank or building society, enabling us to create unique customer scores for all the major providers.
We've also analysed thousands of savings products and given each provider an overall interest rate score, highlighting which companies offer consistently competitive rates. The full results from our most recent analysis (which covers both Isas and savings accounts) are as follows:
RECOMMENDED PROVIDER Moneybox (76) | 83% | 83% | - |
Chase (161) | 81% | n/a | |
RECOMMENDED PROVIDER Marcus by Goldman Sachs (102) | 79% | 86% | - |
Coventry Building Society (102) | 78% | 78% | |
Monzo Bank (210) | 77% | n/a | |
Nationwide Building Society (506) | 77% | 76% | |
RECOMMENDED PROVIDER Yorkshire Building Society (99) | 77% | 88% |
The results are based on an online survey of 4,524 members of the public conducted in August-September 2024. The customer score is based on satisfaction with the brand and likelihood to recommend. Sample sizes in brackets. ‘-’ means not enough responses to include a star rating. The interest rate score is based on analysis of Moneyfacts data collected weekly, between 24 June 2024 and 9 September 2024. An interest rate score of 100 represents the market-leading rate. We only generated an interest rate score for providers that offer accounts without opening restrictions.
Which? Recommended Providers for cash Isas
Each year, we name the best savings providers as Which? Recommended Providers (WRPs). To win this award, the bank or building society must:
- achieve a customer score of 75% or above
- achieve an interest rate score of 80% or above
- be fully covered by the UK Financial Services Compensation Scheme (FSCS)
- not have significant barriers to opening an account, for example high minimum deposit rules or opening restrictions.
- offer products which are available nationally and are not tied to the purchase of another product with the same provider.
This year, our WRPs (in customer score order, rates correct as of 7 July 2025) are:
Moneybox
Moneybox is a new addition to our customer satisfaction table. In its first year offering savings accounts, it has the top customer score. Customers were impressed with its mobile banking app, awarding it five stars.
It currently offers a very competitive instant access cash Isa, with a variable rate of 4.45%. This rate drops to 3.75% after 12 months. It also offers a cash Isa with a variable rate of 4.65%, which drops to 3.95% after 12 months. This Isa allows up to 3 withdrawals per 12-month period without a loss of interest.
Marcus by Goldman Sachs
Marcus by Goldman Sachs received a 79% customer score. Savers gave it top marks for its application process and communication, as well as its mobile app and online banking service.
Marcus currently offers an instant-access savings account and cash Isa that both pay a competitive variable rate of 4.01% AER (3.94% gross), including a 0.49% (gross) bonus rate. This means the rate will fall to 3.5% AER (3.44% gross) after the first 12 months.
Yorkshire Building Society
Yorkshire Building Society earned a customer score of 77%. Savers gave it high ratings for its customer service, application process, regular communications, and online banking service.
It is the only WRP for savings with a branch network. Yorkshire also has the widest range of savings products out of the WRPs.
Its restriction-free instant-access cash Isa offers 3.7% AER.
Zopa
Zopa achieved a customer score of 77%, with customers giving it top ratings for its application process and mobile banking app.
It currently offers an instant access Isa paying 3.75% AER and a four-year fixed-rate Isa paying 3.8% AER.
Can any cash Isas beat inflation?
Inflation fell to 3.4% in May 2025 according to the Office for National Statistics (ONS).
When we checked on 23 June 2025, we found 440 cash Isas (64% of the market) offering an above-inflation interest rate.
You might also want to consider investing in a stocks and shares Isa, which could – though isn't guaranteed to – earn you more interest than a cash Isa.
Find the right savings account for you using the service provided by Experian Ltd. Compare and choose accounts
How to transfer your Isa
If you're transferring your money from one Isa to another, there's only one way to do it: fill in a transfer form with your new Isa provider.
Many providers allow you to do this online. Once you've sent off the form, your new provider will get in touch with your old provider to make the arrangements.
The transfer process should be completed within 15 working days.
Once you've switched Isas, don't rest on your laurels. If the new account has an introductory bonus, make a note of when it ends, as you may want to switch again at that point to make sure you're still getting a good deal.
If it's a variable-rate account, keep an eye on your rate to make sure it stays competitive.
- Find out more: cash Isa rules and allowances