Isa season is here – but are the deals really better?

Savings providers typically hike Isa rates to lure savers racing to use their tax-free allowance before it resets on 6 April. But this year’s Isa season carries extra weight.

The clock is ticking for savers to use their £20,000 cash Isa allowance before it falls to £12,000 for under-65s in April 2027. A planned two-percentage-point rise in tax on savings interest could also leave more people facing a tax bill. 

But are the Isa deals on offer right now really any better than at other times of the year? And could some savers be better off choosing a standard savings account instead? We analysed the latest rates and spoke to Which? members about how they are preparing for next year’s shake-up.

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What is Isa season and are rates really better?

Isa season runs from February to April and serves as a reminder for savers to use up their annual tax-free allowance before it resets at the beginning of the new financial year on 6 April. 

Around 30% of the annual cash Isa haul happens in March and April, according to Hargreaves Lansdown. With so much money coming in over a short period, many banks and building societies increase their rates to tempt new and existing Isa savers.

Moneyfacts data suggests rates are already climbing. The top instant-access cash Isa rate rose from 4.32% AER in February to 4.58% on 5 March 2026.  

Some providers offer other perks to entice new customers. Barclays Bank, for instance, is offering customers who transfer their Isa savings to one of its products up to £600 in rewards. To qualify, you must hold or open a Barclays current account and transfer at least £10,000.

Investment platforms have also launched promotions. Fidelity started Isa season early in January, offering up to £3,000 to customers who deposit a qualifying amount into a stocks and shares Isa before the end of the tax year. 

This table shows the best rates currently available for instant-access and fixed-rate cash Isas, ordered by term:

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• Take a look at our guide to best cash Isas 2026 for help choosing the right provider. 
  

Are the best deals always in spring?

While Isa rates are getting a boost right now, up until recently, it was hard to tell the difference between deals in spring and any other time of year.

A series of Bank of England base rate rises from 2021 pushed savings rates to their highest levels in more than a decade. As a result, competitive deals were widely available throughout the year rather than only during the traditional Isa season.

For example, the top instant-access cash Isa paid just 0.7% AER in March 2022, according to Moneyfacts data. Rates then climbed steadily until December 2023, when the leading deal reached 5.11%.

When the top rate fell in February 2024, it was the first drop in almost two years and reflected the wider savings market.

This graph shows how the top instant-access rate has changed since March 2022:

• Find out more: best savings accounts 2026

Why Isa season matters more this year

Bumper rates aren’t the only reason to consider opening an Isa this spring. From April 2027, the annual cash Isa limit will drop to £12,000 for under-65s. Savers can still use the full £20,000 allowance – but only if £8,000 is invested in a stocks and shares Isa.

Savers appear to have reacted quickly to the Chancellor’s Autumn Budget announcement in November, pouring a record £5.2bn into cash Isas in December 2025 – 47% more than a year earlier and the biggest monthly inflow outside the usual Isa season. 

The rush looks set to continue in 2026 as people try to use their full cash allowance before it’s cut.

Reader voices

Will Isa reforms change how you save?

The upcoming reduction in the cash Isa limit could push more savers to consider investing part of their allowance. But many remain cautious about moving money out of cash.

Which? member Mary told us she is reluctant to move money into a stocks and shares Isa. ‘As an older person, a stocks and shares Isa seems a bit too risky for the short term. The current economic conditions don’t seem right either.’ 

And she's not alone. The results of our survey of more than 1,000 Which? members in December 2025 found that 49% of Which? members still don’t have a stocks and shares Isa. When asked why not, risk was a common reason given. 

Age was also a factor, with older respondents saying they preferred quick access to their savings and more predictable returns.

Others are taking a more flexible approach. Mark told us he is watching what happens to savings rates before deciding what to do with his cash. If rates continue to fall, he says he would consider moving a proportion of his savings into a stocks and shares tracker fund.

‘3% or less interest on savings means cash is at risk of losing value after inflation is taken into account, so I would consider splitting cash and investments 50/50. However, if I can get 4% interest on savings and inflation stays below that, I would probably leave all my savings in a cash Isa.’

Could a cash Isa leave you worse off?

Isas have never been more popular. Around 15 million adult Isa accounts were subscribed to in the 2023-24 financial year, according to the latest HMRC data. Nearly 10 million were cash Isas and around four million were stocks and shares Isas.

But opening a tax-free account doesn’t always mean you’ll earn more.

Many savers won't pay tax on their interest 

Most people get a personal savings allowance (PSA), which shields a portion of interest earned on savings from income tax. The PSA currently stands at £1,000 for basic-rate taxpayers and £500 for higher-rate taxpayers. Additional-rate taxpayers don't have a PSA, meaning all their savings interest is subject to income tax.

New analysis by Paragon Bank shows 8.6 million non-Isa adult savings accounts, and £634bn in balances, are now generating enough annual interest to exceed the £500 PSA. But the reality is, unless you have a large sum of money stashed in a market-leading savings account, you're probably unlikely to get stung by the taxman. 

For example, a basic-rate taxpayer opening today's top instant-access account earning 4.5% AER would need a balance of just over £22,000 before they exceed their PSA. That drops to just over £11,000 for a higher-rate taxpayer.

• Find out more: what tax do you pay on savings interest?

Savings accounts sometimes pay better rates

Cash Isas don’t always offer the best returns.

Using Moneyfacts data from 5 March 2026, we compared the average top 10 rates on standard savings accounts with the equivalent top cash Isa deals. Non-Isa accounts came out ahead or matched Isa rates across every product type we looked at.

Instant-access accounts and cash Isas both paid an average of 4.25% AER. But one-year fixed bonds paid 4.21% compared with 4.09% for the Isa equivalent, while five-year deals paid 4.21% compared with 4.11%.

That difference may sound small, but it can still affect returns. With £10,000 saved for a year at today’s average top rates, a standard savings bond would earn around £16 more interest than a cash Isa.

For savers who won’t pay tax on their interest, that means choosing an Isa could leave them with slightly lower returns.

Higher-rate taxpayers benefit most 

Opening a cash Isa may mean accepting a slightly lower headline rate, but once tax comes into play, you could still end up better off than with a higher-rate savings account.

If you had a lump sum £20,000 and you put that into a standard instant-access account, a one-year fix or a five-year bond paying the average top rate. A basic-rate taxpayer wouldn’t pay any tax on the interest, and you’d actually come out a little ahead compared with putting the same amount into a cash Isa.

For higher-rate taxpayers, though, the picture changes. After tax is taken into account, the best instant-access cash Isa could leave you £140 better off over a year than the top standard savings account, assuming rates stay the same. The difference is £113 with a one-year fix and £117 over five years.

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3 ways to make the most of your Isa

Here are our top tips to help savers and investors make the most of their accounts:

1. Mix and match for the best returns

Savvy savers and investors can split their £20,000 allowance across multiple Isas, even if they are the same type of product. You could, for example, stash a portion of savings in the highest-interest cash Isa on the market and then play the long game by placing the rest of your allowance in a stocks and shares Isa.

Or you can split cash Isa savings across an instant access account and a fixed-rate account that locks up your money for longer, for example. 

2. Make it a family affair

If you've used up your annual £20,000 Isa allowance, but your partner hasn't, you can pay into their account instead, effectively increasing your shared Isa allowance to £40,000.  

If you want to save for your child, you could open a Junior Isa on their behalf. Junior Isas have an annual allowance of £9,000.

Between them, a family of four could potentially save £58,000 a year tax-free in Isa accounts.

3. Consider opening a stocks and shares Isa

While opening a cash Isa will help shield your savings from income tax, a stocks and shares Isa can help you sidestep paying capital gains tax (CGT) on your investments. 

Stocks and shares products let you invest up to £20,000 a year without having to pay a penny in CGT. Plus, any income such as interest or dividends will also be free from tax.

However, if you already hold investments, you can't transfer them into your Isa. Instead, you can opt to sell them, transfer the money to your Isa, and use that cash to buy the investments back – this is known as 'Bed and Isa'.