Fixed rate cash ISAs: terms, early access charges and maturity

A fixed rate cash ISA is a tax-free savings account that pays an interest rate which stays the same for a set period, typically one, two, three, four or five years¹. In exchange for that certainty, you lock your money away: Coventry Building Society describes a fixed rate ISA as a tax-free savings account offering a higher interest rate in exchange for locking your money away for a fixed term², and Yorkshire Building Society sums up the trade-off as being good for lump sums you do not need access to, with the rate staying the same for the term³.

The other side of the bargain is access. Fixed rate cash ISAs require you to keep your money in the account for a certain period, so you may face a penalty if you take it out early⁴. Those penalties typically range between 90 and 365 days of lost interest⁵, and in the worst case you can get back less money than you paid in. This page explains how the terms work, what early access costs, how transfers in and out are handled, and what happens when the fixed term ends.

What a fixed rate cash ISA offers: a set rate for a set term

The defining feature of a fixed rate cash ISA is predictability. NS&I's guidance is that fixed rate cash ISAs give you an interest rate which stays the same over a set period, typically 1, 2, 3, 4 or 5 years¹. Whatever happens to interest rates in the wider market during that time, the rate on your account does not move, and you know exactly what the account will pay from the day you open it.

That is the main reason people choose one. Coventry Building Society describes the deal as a higher interest rate in exchange for locking your money away for a fixed term², and Yorkshire Building Society's guide frames it the same way: these accounts suit lump sums you do not need access to, because the rate stays fixed for the term³. Providers present the fixed rate as the reward for giving up flexibility, and Virgin Money's key facts describe the product simply as a fixed interest rate for a fixed period of time¹⁰.

How interest is paid varies between accounts and matters for what you can do with it. Tandem advertises fixed monthly interest on its savings range¹¹, which suits someone who wants the interest as income during the term, while other accounts pay interest annually or at maturity. Because the interest is earned inside an ISA, it is tax-free whatever the payment schedule, and it does not eat into your allowance (covered below).

The comparison worth making before fixing is with accounts that let you get at your money. An easy access cash ISA pays a variable rate you can withdraw at any time without charge, while a fixed rate account pays a known rate but charges you to leave early. The page on fixed rate or easy access cash ISAs sets the two side by side, and cash ISAs explained covers the wider cash ISA market.

Terms usually run from one to five years

Most fixed rate cash ISAs run for between one and five years. Leeds Building Society states that the interest rate is guaranteed for the duration of the ISA, from 1 to 5 years¹², and Monmouthshire Building Society says its fixed rate Cash ISA locks in your interest for a set term, usually 1 to 5 years¹³. Cambridge Building Society's guidance is that your money may be locked away for a set amount of time, usually under 5 years¹⁴, while Furness Building Society puts the same point as anything from one year to five years depending on the account you choose¹⁵.

Not every provider offers the full range. Ford Money's Fixed Cash ISA is available over 1, 2 or 3 years¹⁶, and Cynergy Bank advertises 1 year, 2 year and 3 year fixed rate terms alongside its variable options¹⁷. When comparing accounts, the term is the first thing to settle: a 1 year fixed rate ISA ties your money up for a much shorter period, but longer terms are where providers typically offer their higher fixed rates in return for the longer commitment.

The term also sets the shape of the early access charge, covered below. Charges are usually expressed in days of interest, and a five year account tends to carry a larger charge than a one year account because there is more of the term left to run when you leave. The exact charge for any specific account is always stated in its terms, so it is worth reading them before committing rather than assuming the typical range applies.

Tax-free interest and the £20,000 allowance

Interest earned in a cash ISA is free of income tax, and the amount of new money you can pay into ISAs is capped at £20,000 per tax year. Ulster Bank states its savings offer tax-free interest on balances up to £20,000⁷, and Which? confirms you can currently hold up to £20,000 a year in an ISA tax-free¹⁸. That allowance covers all your ISAs together, not each one, so money paid into one fixed rate cash ISA reduces what can be paid into any other ISAs that tax year. The page on the ISA allowance explains how the limit works, and ISAs and tax covers what is and is not tax free.

Two things do not use the allowance. First, interest you earn: Which? reports that the interest you earn in a cash Isa does not count towards your allowance¹⁹, so a £20,000 deposit that grows stays inside the ISA without any new subscription. Second, transfers in from existing ISAs, which move money you have already sheltered in previous tax years. The page on whether transferring uses your allowance covers that in detail.

The tax-free treatment is separate from the personal savings allowance, the amount of interest you can earn outside an ISA before paying tax. Government guidance states plainly:

HM Treasury, ISA reform factsheet⁶

That cuts both ways: ISA interest is tax-free so it never needs the allowance, but it also does not consume it. Age UK makes the same point, noting that savings in tax-free accounts like Individual Savings Accounts do not count towards this allowance²⁰. So if you have used your personal savings allowance on ordinary savings accounts, money moved into a fixed rate cash ISA earns interest with no tax consequence at all. NS&I says the same of its Direct ISA: the interest you earn is tax-free, so it will not count towards your Personal Savings Allowance²¹.

Early access charges: what leaving before the end costs

The charge for getting at your money early is the single most important term in a fixed rate cash ISA. Which?'s guide to cash ISA rules warns that fixed rate cash Isas require you to keep your money in the account for a certain period, so you may face a penalty if you access it early⁴. The typical scale of that penalty is between 90 and 365 days of lost interest for early closure or withdrawal⁵.

The charge is usually worked out as a number of days of interest on the amount you withdraw, and the number of days varies by account and by how much of the term remains. Because the charge comes out of interest first, an account closed very early in its term may not yet have earned enough interest to cover it. In that case the shortfall is taken from the money you paid in, which is how you can end up with less cash back than you deposited. The exact charge is always set out in the account terms, and it differs from one provider to the next, so the typical range is a guide, not a promise.

Which? also notes that fixed-rate accounts may charge an interest penalty if you withdraw money or close the account before the fixed period ends, which applies to transfers out as well as cash withdrawals²². That is worth checking before you start any move: transferring a fixed rate ISA to another provider mid-term is treated as leaving early, and the charge applies in the same way.

The practical test before fixing is whether the money is genuinely spare. Which?'s reporting on emergency savings suggests working out how much you would need to fall back on, and money you may need at short notice is better held where it can be reached without charge¹⁸. Splitting savings between a fixed rate ISA for the lump you will not touch and an easy access account for the rest is a common way to manage that, and the savings section covers the wider range of accounts.

Transfers in and out before the term ends

You can move money into a fixed rate cash ISA from other ISAs, and providers such as Family Building Society state that transferring existing ISAs is part of how these accounts work²². The transfer has to be done through the official transfer process rather than by withdrawing the money yourself: cash that is withdrawn and then repaid counts as new money against the current year's £20,000 allowance, whereas a transfer preserves its ISA status. The pages on how to transfer an ISA and how long a transfer takes cover the process step by step.

Transfers out before the end of the term are where the early access charge bites. Which? notes that fixed-rate accounts may charge an interest penalty if you withdraw money or close the account before the fixed period ends, and a transfer out counts as doing that²². So moving a fixed rate ISA elsewhere mid-term is possible, but it usually costs the same as withdrawing the money. Some savers judge that worth paying to escape an account, but the charge should be weighed against the benefit of the move first.

The stages of a fixed rate cash ISA, from paying in to the end of the term.

One further point on transfers in: the deposit window matters. Because most fixed rate cash ISAs stop accepting money shortly after opening, a transfer arriving late can be a problem. HSBC, for example, allows additional money to be added to its Fixed Rate Cash ISA only within the first 30 days of the account opening, subject to conditions⁹. If you are transferring a large existing ISA in, it is worth confirming with the receiving provider how the timing works before opening the account.

At maturity: the choices when the term ends

When the fixed term ends, the account reaches maturity and the early access charge falls away: the money can then be withdrawn or moved without penalty, because the period the charge protected is over. Monmouthshire Building Society's maturity guidance is built around exactly this moment, helping customers whose fixed rate Cash ISA, which locks in interest for a set term of usually 1 to 5 years, has come to the end of that term¹³. The fixed rate itself also stops applying, so leaving the money where it is means it no longer earns the rate you signed up for.

At that point there are three broad options: move the money to a new fixed rate cash ISA, transfer it to a different type of ISA or savings account, or leave it in the matured account. Which suits you depends on whether you still want to lock the money away, whether you need access to it now, and what the provider's terms say happens to balances after maturity. Because the money is already inside the ISA wrapper, moving it on by transfer does not use the current year's allowance, which is why the maturity date is a natural point to review the account rather than let it drift.

HSBC's maturity guidance for its Fixed Rate Cash ISA illustrates how providers handle the transition, including the option to add more money to a new fixed account within the first 30 days of it opening⁹. Providers typically write to customers before the term ends, and the pages on taking money out of an ISA and the ISA deadline and the end of the tax year explain the timing rules that apply around moving money.

Who can open one and how applications work

The eligibility rules are the standard cash ISA rules, covered in full on who can open an ISA. In brief, you need to be a UK resident, and cash ISAs are unusual in being available from age 16, younger than most other ISA types. There is no joint option: Which? is clear that you cannot have two account holders on a cash Isa, so couples cannot use them to save together⁸, and the page on whether an ISA can be held in joint names covers the alternatives. Each person opens their own ISA and each gets their own £20,000 allowance.

There is no limit on how many you hold. Yorkshire Building Society states you can open as many fixed rate cash ISAs as you like²³, though the £20,000 allowance on new money still applies across all of them each tax year. Opening an account is usually straightforward: most providers offer online applications, and building societies typically also accept applications in branch or by post. Minimum deposits vary, from £500 on Paragon's one year fixed cash ISA²⁴ and £1,000 on Shawbrook's fixed rate cash ISAs²⁵ to £1,000 on Melton Building Society's accounts²⁶, so the entry point is worth checking if you are starting with a smaller sum.

Maximum balances vary even more widely, and this is where accounts genuinely differ:

These are account limits, not tax limits: the £20,000 allowance governs new money going in each year, while balances above that come from transfers in or interest earned over time. The conflict in these figures is real and unresolved, so treat the table as examples of the range rather than a rule.

Who provides fixed rate cash ISAs in the UK

Fixed rate cash ISAs are offered across the market, by high street banks, building societies and specialist savings banks. NS&I, the government-backed savings provider, includes fixed rate cash ISAs in its ISA guidance and offers its own Direct ISA¹. Among the banks, HSBC offers a Fixed Rate Cash ISA with a defined maturity process⁹, Ulster Bank includes cash ISAs in its savings range⁷, Cynergy Bank offers 1, 2 and 3 year fixed terms¹⁷, Tandem advertises fixed monthly interest on its savings range¹¹, and Secure Trust Bank offers a 5 year fixed rate cash ISA³¹.

Building societies are a strong presence in this market. Leeds Building Society guarantees its rate for the duration of the ISA, from 1 to 5 years¹²; Coventry Building Society describes the fixed rate ISA as a higher rate in exchange for locking money away²; Yorkshire Building Society publishes a dedicated guide to fixed rate cash ISAs²³; and Cambridge¹⁴, Furness¹⁵, Monmouthshire¹³, Saffron³⁰ and Melton²⁸ all offer fixed rate cash ISA accounts. Ford Money offers a Fixed Cash ISA over 1, 2 or 3 year terms¹⁶, Shawbrook offers fixed rate cash ISAs with a £1,000 minimum²⁵, and Paragon offers both 1 year and 5 year fixed cash ISAs²⁴. Virgin Money's fixed rate cash ISA exclusives are set out in its key facts document¹⁰.

The differences between them that matter to a saver are practical: the terms on offer, the minimum and maximum balances, how interest is paid, and the size of the early access charge. All of these are stated in each account's summary box and terms, and comparing them directly is more useful than comparing brand names. The banks and building societies directory lists providers, and ISA fees and charges covers what to look for in the small print.

Protection, complaints and free help

Money held with an ISA provider is protected by the UK's deposit protection scheme up to the standard limit, in the same way as other savings accounts with the same provider. The level of cover and how it interacts with the ISA wrapper is explained on how your ISA is protected. One point worth knowing is that protection applies per banking licence, so if you hold savings and an ISA with two brands that share a licence, their balances count together towards the limit.

If something goes wrong, start by complaining to the provider, and if it does not resolve the matter, the Financial Ombudsman Service can look at it. The process is set out on complaining about an ISA provider. For free, impartial help with money questions, MoneyHelper offers government-backed guidance, and the consumer protection section explains your rights across UK financial services.

Two further protections are worth noting. If you change your mind shortly after opening, ISAs come with a cooling-off right, covered on cancelling an ISA. And if a transfer between providers is slow, you may be entitled to compensation, explained on compensation for a delayed ISA transfer. Neither removes an early access charge that applies under the account's terms, but both give you recourse when a provider has not followed the rules.