Best 18 Month Year Fixed Rate ISAs
We found 13 PRODUCTS in total, of which 1 are EASY TO OPEN
TSB Fixed Rate Cash ISA
In the UK, the first £120,000 of savings per person is protected by the Financial Services Compensation Scheme. Some banking brands share the same banking licence which means your deposit protection is across all brands sharing the licence. If you have also borrowed from the failed bank/building society, the compensation will not be reduced to repay your debt, separate arrangements will be made for this. The deposits of most businesses are covered up to the £120,000 limit, but businesses should check with their bank before they apply as there are exclusions.
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In the UK, the first £120,000 of savings per person is protected by the Financial Services Compensation Scheme. Some banking brands share the same banking licence which means your deposit protection is across all brands sharing the licence. If you have also borrowed from the failed bank/building society, the compensation will not be reduced to repay your debt, separate arrangements will be made for this. The deposits of most businesses are covered up to the £120,000 limit, but businesses should check with their bank before they apply as there are exclusions.
In the UK this bank/building society shares its compensation limit with
Stroud & Swindon BS.
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In the UK, the first £120,000 of savings per person is protected by the Financial Services Compensation Scheme. Some banking brands share the same banking licence which means your deposit protection is across all brands sharing the licence. If you have also borrowed from the failed bank/building society, the compensation will not be reduced to repay your debt, separate arrangements will be made for this. The deposits of most businesses are covered up to the £120,000 limit, but businesses should check with their bank before they apply as there are exclusions.
Kellands are chartered financial planners that specialise in quality financial planning and investment advice. Learn more about speaking to Kellands for a one hour consultation free of charge. Min. £100k in savings & investments.
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In the UK, the first £120,000 of savings per person is protected by the Financial Services Compensation Scheme. Some banking brands share the same banking licence which means your deposit protection is across all brands sharing the licence. If you have also borrowed from the failed bank/building society, the compensation will not be reduced to repay your debt, separate arrangements will be made for this. The deposits of most businesses are covered up to the £120,000 limit, but businesses should check with their bank before they apply as there are exclusions.
_All_125x100.png)
In the UK, the first £120,000 of savings per person is protected by the Financial Services Compensation Scheme. Some banking brands share the same banking licence which means your deposit protection is across all brands sharing the licence. If you have also borrowed from the failed bank/building society, the compensation will not be reduced to repay your debt, separate arrangements will be made for this. The deposits of most businesses are covered up to the £120,000 limit, but businesses should check with their bank before they apply as there are exclusions.
In the UK this bank/building society shares its compensation limit with
Newcastle BS.
_All_125x100.png)
In the UK, the first £120,000 of savings per person is protected by the Financial Services Compensation Scheme. Some banking brands share the same banking licence which means your deposit protection is across all brands sharing the licence. If you have also borrowed from the failed bank/building society, the compensation will not be reduced to repay your debt, separate arrangements will be made for this. The deposits of most businesses are covered up to the £120,000 limit, but businesses should check with their bank before they apply as there are exclusions.
_All_125x100.png)
In the UK, the first £120,000 of savings per person is protected by the Financial Services Compensation Scheme. Some banking brands share the same banking licence which means your deposit protection is across all brands sharing the licence. If you have also borrowed from the failed bank/building society, the compensation will not be reduced to repay your debt, separate arrangements will be made for this. The deposits of most businesses are covered up to the £120,000 limit, but businesses should check with their bank before they apply as there are exclusions.
_All_125x100.png)
In the UK, the first £120,000 of savings per person is protected by the Financial Services Compensation Scheme. Some banking brands share the same banking licence which means your deposit protection is across all brands sharing the licence. If you have also borrowed from the failed bank/building society, the compensation will not be reduced to repay your debt, separate arrangements will be made for this. The deposits of most businesses are covered up to the £120,000 limit, but businesses should check with their bank before they apply as there are exclusions.
_Savings_125x100.png)
In the UK, the first £120,000 of savings per person is protected by the Financial Services Compensation Scheme. Some banking brands share the same banking licence which means your deposit protection is across all brands sharing the licence. If you have also borrowed from the failed bank/building society, the compensation will not be reduced to repay your debt, separate arrangements will be made for this. The deposits of most businesses are covered up to the £120,000 limit, but businesses should check with their bank before they apply as there are exclusions.
In the UK this bank/building society shares its compensation limit with
Holmesdale BS.
In the UK, the first £120,000 of savings per person is protected by the Financial Services Compensation Scheme. Some banking brands share the same banking licence which means your deposit protection is across all brands sharing the licence. If you have also borrowed from the failed bank/building society, the compensation will not be reduced to repay your debt, separate arrangements will be made for this. The deposits of most businesses are covered up to the £120,000 limit, but businesses should check with their bank before they apply as there are exclusions.
In the UK this bank/building society shares its compensation limit with
Holmesdale BS.
Eligible deposits with UK institutions are protected by the FSCS up to £120,000 per person per institution.
Who owns whom?
Find out which banks and savings account providers operate under which banking license with our who owns whom guide, helping savers work out to what degree their savings are protected by the FSCS.
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An 18-month cash ISA is simply a type of fixed ISA that pays a guaranteed rate for 18 months. This means the interest rate won’t change for this period, giving you a predictable return on your money.
As with other ISAs, the interest earned is exempt from income tax.
These accounts could be useful for savers who want to put money towards a short-to-medium term goal, such as a wedding, a holiday or a new car, for example, as they won’t be tempted to dip into this money for any other purpose. Just make sure the 18-month term ends before you need to access your savings, as the provider will usually apply a penalty if you want to withdraw before the end of the fixed period.
After opening an 18-month cash ISA, you will need to add money to your account.
Depending on the provider, you may only be able to make one deposit when you open the account, but others may allow further additions for a limited period, such as 14 or 28 days.
Bear in mind that you can only deposit a maximum of £20,000 across one or more cash ISAs in a single tax-year.
In return for receiving a guaranteed rate, you typically won’t be able to withdraw from your savings (or transfer to a different ISA) during the 18-month period without incurring some form of penalty.
At the end of the 18-month term, the provider will often move your money into a standard variable ISA or other type of ISA unless you request otherwise.
While savers can currently deposit £20,000 into cash ISAs each tax-year, the ISA allowance rules are changing from April 2027. When the new rules come into effect, the cash ISA allowance will be cut to £12,000 for those aged under 65, although those aged over 65 will still be able to save up to £20,000 into cash ISAs each year.
More details on how this change will be introduced are yet to be confirmed.
To open an 18-month cash ISA, you need to be a UK resident aged 18 or over. Crown employees and members of the armed forces serving abroad (and their spouses or civil partners) are also eligible to open an ISA.
When applying, you need to tell the provider some key details, such as your:
If you’re transferring in from another ISA, you’ll also need to give the provider the details of this account.
If you want to transfer an existing ISA to an 18-month ISA, check if the provider accepts transfers into the account. Not all 18-month ISAs accept ISA transfers, or may only accept transfers in from certain types of ISA, so always double-check this if you’re planning to move money from one ISA to another.
The way you can manage your 18-month ISA depends on the provider.
For example, you may be able to manage it online, via mobile app, by phone, in branch or by post. Some providers offer multiple management methods while others may only offer one.
You can see the different ways you can manage each ISA on our chart.
Minimum deposit requirements vary between ISAs and providers.
You may be able to open some 18-month ISAs with as little as £1 but others may ask for several thousand pounds.
Click “view further details” next to an account on our chart to see the minimum deposit required.
Make sure you check if you can add to your savings after your initial deposit. Some may only allow one deposit, which means you need to think carefully about how much you add to your account, while others allow you to add to your savings for a limited period after opening.
Providers will have their own set of terms and requirements, such as a minimum opening deposit (as discussed above).
But, as well as the requirements of an individual account, it’s important to think about the general terms and conditions of opening an ISA, particularly your annual ISA allowance.
While you can have and open multiple cash ISAs within the same tax-year, you can only pay in a maximum of £20,000 across all your ISAs.
So, if you’re saving into one or more ISAs alongside an 18-month ISA, make sure you keep track of how much you deposit in all of these accounts.
It’s up to you to decide whether an 18-month ISA is right for you or whether you should fix for a longer term. These accounts are a kind of middle-ground between short- and long-term ISAs and may appeal to savers who want to secure a guaranteed rate but aren’t comfortable locking away their money for two years or more. You will be able to access your savings after 18 months, so it’s not as much of a commitment as depositing a lump sum in a two- or three-year ISA, for example.
However, if you have some money that you’re confident you won’t need to access in the near future, it may be worth securing a fixed return for a longer period. This would protect your savings from any future drops in rate (as the interest rate will be fixed for the specified period), but, on the other hand, if interest rates rise during the term, you could miss out on higher-paying accounts. Researching how savings rates are expected to change over the coming years can help to inform your decision on how long to lock in a rate for, but remember that interest rates may not always move as predicted.
As well as the market, it’s important to think about your individual situation when deciding whether an 18-month ISA or an ISA with a different length term is more suitable. Ask yourself how long you are willing to lock away access to a portion of your savings and when you are likely to need it, taking into consideration the money you have saved elsewhere.
Furthermore, it’s not necessarily a case of choosing an 18-month ISA or a longer-term ISA; you could have multiple ISAs with different term lengths. This can be a useful way to “ladder” your savings so you can access some of your money when one account matures, while the rest continues to earn interest in a separate account.
Before locking money away in an 18-month ISA (or any other fixed account), ensure you have an emergency fund saved in an easy access account. It’s important to have this financial cushion that you can dip into at short notice so you can cover any unexpected expenses or temporary drops in income. Read more on how to save up an emergency fund.
Instead of an 18-month ISA, you may want to consider a one-year ISA or two-year ISA, which are more common products. As a result, you’re likely to have more accounts to choose from and may be able to secure a more competitive rate than if you only looked at 18-month ISAs.
If you want a fixed ISA with a longer term, you could also consider a three- or five-year fixed ISA.
Alternatively, if you want the option to dip into your savings, easy access ISAs or notice ISAs could be suitable options.
You may also want to look at standard savings accounts, such as an 18-month bond, instead of ISAs as you may find these pay higher rates.
However, it’s important to bear in mind that you will need to pay tax on any interest you earn from your savings if you earn more than your Personal Savings Allowance (PSA). By contrast, you don’t need to pay any tax on interest you earn on ISAs.
Note that the tax benefits depend on your personal circumstances and may change in the future.
You can view the latest 18-month ISA rates on our chart above. At the start of 2026, the top accounts pay in excess of 3.50% AER.
Because one- and two-year ISAs are more common than 18-month ISAs, you may be able to find more competitive rates on these accounts.
If you saved your full ISA allowance of £20,000 in an 18-month ISA paying an interest rate of 3.50%, your savings could be worth approximately £21,050 at the end of the term.
The main disadvantage of an 18-month ISA is that there aren’t many options to choose from. There are more ISAs available with one- or two-year terms, so these accounts may offer higher rates than the best 18-month ISA.
This depends on the provider. Once you’ve made your initial deposit, some providers may allow you to add to your savings for a limited period of time after opening, such as 14 or 30 further days. However, other providers may not permit any further contributions after your initial deposit.
By contrast, variable ISAs typically allow you to add to your savings without restriction (within your ISA allowance).
There isn’t a fixed maximum balance you can hold in an 18-month ISA, but providers may set their own limits. Even if a provider doesn’t set a maximum limit, remember you can only deposit up to £20,000 in ISAs each tax-year and only up to £120,000 you have saved with a banking provider is covered under the Financial Services Compensation Scheme (FSCS).
If you want to access your money before the end of the 18-month term, this will usually be subject to a loss of interest penalty charge. For example, some providers may deduct a penalty charge of 90 days’ interest, or potentially even more.
Depending on how far into the term you request the withdrawal, you could end up losing the interest you’ve already earned, and you could even get back less than you deposited.
Yes, you can transfer existing ISAs into a new 18-month ISA. Read more in our guide to transferring ISAs.
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