Fixed Rate or Easy Access Cash ISA

A Cash ISA holds cash rather than investments, so the money you put in cannot go down, and the interest is tax free¹. The choice between a fixed rate and an easy access version comes down to one trade-off: whether you can leave the money alone.

An easy access Cash ISA pays a variable rate and lets you withdraw any time². A fixed rate Cash ISA pays a set rate for a set period, typically one, two, three, four or five years, and you usually cannot take money out during that term without a penalty¹. The longer you can commit, the more certainty you get about what you will earn.

There is a second change on the horizon. From 6 April 2027, the amount under-65s can pay into a Cash ISA each tax year falls to £12,000, within an overall ISA allowance that stays at £20,000³. Savers aged 65 and over keep the full £20,000 cash allowance⁴. That makes the decision about how much to lock away, and for how long, more pointed than it used to be.

Easy access Cash ISAs: withdraw any time, variable rate

An easy access Cash ISA, sometimes called an instant access Cash ISA, lets you take money out whenever you want, and the interest rate is normally variable, so it can change². Providers describe the access plainly: "Withdraw anytime"⁸. One provider's key facts describe the rate as a "Variable interest rate. This means the rate may change."⁹

That flexibility is the point. It suits money you might need at short notice, such as an emergency fund, because you are not locked in and there is no charge for taking your own money out. The trade-off is that the rate is not guaranteed. It can fall, and it can rise, at the provider's discretion.

The gap between what easy access and fixed rate pay is not fixed either. In 2025-26, fixed rate standard savings accounts paid higher rates on average than fixed rate cash ISAs, and instant access savings accounts also paid higher rates on average than instant access cash ISAs, though there were three months in which average cash ISA rates were on top¹⁰. That is a reminder that the ISA wrapper does not automatically carry the highest rate on the market; it is the tax treatment that makes it worth comparing.

For money you may need to reach, the easy access version is the one that does not punish you for doing so. For money you will not touch, the fixed version usually pays more, and the difference can be worth having. One comparison found a difference of more than a percentage point between the best easy-access and top fixed-rate deal¹¹.

Fixed rate Cash ISAs: a set rate for 1 to 5 years

A fixed rate Cash ISA gives you an interest rate that stays the same over a set period, typically one, two, three, four or five years¹. Providers set their own terms: some offer one, two and three year fixed rate terms¹², others a five year term¹³, and building societies commonly describe locking in interest for a set term, usually one to five years¹⁴.

The appeal is certainty. You know what you will earn for the whole term, and the rate cannot be cut while you are in it. That makes a fixed rate Cash ISA easier to plan around than a variable one, particularly if you are matching the money to a known future cost.

The cost of that certainty is access. Fixed rate cash ISAs usually do not allow access until the end of the fixed period¹⁵, and you may face a penalty if you access the money early¹⁶. Some providers are explicit that the money is locked away for a set amount of time, usually under five years¹⁷.

Fixed rate terms are not all the same length, and the rate usually reflects how long you commit for. A one year fix and a five year fix are different products with different risks: the shorter one frees your money sooner but exposes you to whatever rates are available when it ends, while the longer one locks in today's rate for longer, which helps if rates fall and hurts if they rise.

Getting money out early from a fixed rate ISA

If you need money that is inside a fixed rate Cash ISA before the term ends, the consequences depend on the provider's terms. You could incur a charge if you take your cash out before the end of the term, whereas easy access versions let you withdraw free of charge⁷. In some cases you might have to pay a charge or even close your account to pull it out early¹⁸.

That is the risk to weigh before you commit, not after. A fixed rate Cash ISA is a poor home for an emergency fund, because the moment you need it is the moment the penalty bites. Money you might need at short notice belongs somewhere you can reach it without a cost.

The practical approach many savers take is to split their money. Keep enough in an easy access Cash ISA to cover the unexpected, and fix only the money you are confident you will not need for the length of the term. That way a surprise does not force you into a penalty.

A balance transfer moves the debt, not the interest rate

The same logic that applies to any fixed term applies here: the rate is only half the deal, and access is the other half. A fixed rate Cash ISA that pays more but locks your money for five years is not better or worse than an easy access one in the abstract. It depends on whether the money is genuinely spare for that long.

If you are unsure, the shorter fixed terms exist for exactly that reason. A one year fix commits you for less time than a five year fix, and the rate difference between them is the price of that flexibility. There is no single right answer, only a match between the term and when you will actually need the money.

The Cash ISA allowance for under-65s falls to £12,000

The rules around how much you can put into a Cash ISA are changing. From 6 April 2027, the annual cash ISA subscription limit falls to £12,000 for individuals aged under 65¹⁹. The overall annual ISA limit stays at £20,000, so the remaining £8,000 can go into other ISA types⁵.

Savers aged 65 and over keep the full £20,000 cash ISA allowance⁴. The government has confirmed that for investors aged 65 or over the annual subscription limit for a cash ISA will remain at £20,000²⁰. The change is set out in legislation: Regulation 6 introduces a £12,000 limit on subscriptions to cash ISA accounts for individuals under the age of 65²¹.

There are anti-circumvention rules alongside the change, designed to stop people getting around the reduced cash limit by holding cash inside other ISA types. From 6 April 2027 there will be no transfers from stocks and shares and Innovative Finance ISAs to cash ISAs, tests to determine whether an investment is eligible to be held in a stocks and shares ISA or is "cash like", and a charge on any interest paid on cash held in a stocks and shares or Innovative Finance ISA²². That charge is a flat rate of 22% on interest or alternative finance return on cash held in a non Cash ISA²².

For anyone planning a fixed rate Cash ISA now, the term matters against this date. A five year fix opened today runs past April 2027, so the amount you can put into cash ISAs in future tax years will be lower if you are under 65. That does not change the terms of an ISA you already hold, but it changes how much new money you can add to cash each year.

FSCS protection: up to £120,000 per person, per bank

Cash ISA deposits are protected by the Financial Services Compensation Scheme. The limit is £120,000 per eligible person, per bank, building society or credit union⁶. The scheme protects up to £120,000 per person or company, per authorised firm²³, and NS&I states it is normally up to the value of £120,000 per person²⁴.

The limit rose to £120,000 on 1 December 2025; before that it was £85,000²⁵. That matters if you hold savings across more than one account with the same provider, because the limit applies per institution, not per account. Money in several accounts with the same bank counts together towards one £120,000 limit.

Protection covers deposits at FCA or PRA authorised UK banks and building societies²⁶. It applies to Cash ISAs in the same way as any other savings account: one provider states that cash ISAs with banks and building societies are protected by the Financial Services Compensation Scheme²⁷. The FSCS also notes that temporary high balances may be protected above the limit for six months in certain circumstances²⁸.

What happens when a fixed rate Cash ISA matures

A fixed rate Cash ISA does not simply stop at the end of its term. Providers typically move the balance into an easy access or instant access account. One building society states that at the end of the fixed rate term the account will automatically become an Easy Access Cash ISA or the nearest equivalent available at that time²⁹. Another says the fixed rate ISA will mature into an Instant Access Cash ISA, earning the standard variable rate³⁰.

That default is worth understanding, because the standard variable rate is often lower than the fixed rate you had. If you do nothing, your money keeps earning, but probably less. The maturity process usually gives you a window to move the money to a new fixed deal or transfer it to another provider, and using that window is how you avoid drifting onto a lower rate.

The same applies to the term itself. A fixed rate Cash ISA that matures in 2027 or 2028 will return your money at a point when the cash ISA rules have changed, so the amount you can put back into a cash ISA in that tax year will reflect the new limit if you are under 65.

Can I have both a fixed rate and an easy access Cash ISA?

Yes. You can pay into as many ISAs as you like in a tax year, as long as the total stays within your annual allowance¹⁰. There is no rule that says you must choose one type. Many savers hold an easy access Cash ISA for money they might need and a fixed rate Cash ISA for money they will not touch, and both count towards the same overall limit.

A flexible ISA adds another option. A flexible ISA allows you to withdraw money and pay it back in again within the same tax year without it affecting your ISA allowance¹. So if you take money out and replace it before the tax year ends, you have not used up any allowance. Providers are not obliged to offer flexibility, so it is worth checking the terms if that matters to you¹⁰.

The allowance itself does not roll over. You cannot carry over unused ISA allowance into the next tax year, and your allowance resets every 6 April¹. If you do not use it, you lose it³¹. That is why the timing of a fixed rate decision matters: money you fix for five years uses this year's allowance, and next year's allowance is a fresh amount.

Where to get help

If you are unsure which type suits your circumstances, free and impartial guidance is available. MoneyHelper, the government-backed money guidance service, covers savings and ISAs, and the Financial Ombudsman Service can look at complaints about an ISA provider if something goes wrong. For debt problems, free advice charities can help you work out whether saving or repaying debt comes first.

The decision itself is yours, and it turns on facts only you know: when you will need the money, and how much of it you can genuinely leave alone. A fixed rate Cash ISA rewards patience with a set rate; an easy access one rewards flexibility with a variable rate and no penalty for withdrawal. Matching the term to the money is the whole of the choice.