skip to main content
Cash ISAs / Fixed Rate Cash ISAs /

18 Month Fixed Rate ISA

Compare Latest Fixed Term ISA Deals

Use your ISA allowance wisely by comparing our selection of market-leading 1 year fixed rate ISAs to maximise your tax-free returns.

Fixed Rate Cash ISAs

1 Year Triple Access Cash ISA

from Nationwide

Interest Rate (AER) 0.25%
  • Term: 1 Year, with option to make three free withdrawals
  • Make up to three withdrawals during the 12-month term of this account
  • Open with £1 or transfer in existing ISA funds
  • Manage your account online
  • Interest paid at maturity
  • FSCS Protected
  • Must be UK resident and aged 16 or older
  • Make more than three withdrawals and the rate drops to 0.01% AER/gross p.a. (variable)
  • Not available in branch

Calculate your interest with this plan

Your savings:
You could gain:
£0.00 (per tax year)


Individual savings accounts, also known as ISAs, are savings accounts that offer you the ability to earn a certain amount of tax-free interest, set by the government each year. You can open an ISA through the majority of high street banks and there are plenty of different ISA accounts available in the UK.

  1. Cash ISAs or instant access ISAs: This kind of ISA may be ideal for you if you are likely to use your savings in the near future, as they often allow you to make a withdrawal of any size at any time.
  2. Fixed rate ISAs: This ISA requires you to lock up your capital for an agreed time period. Banks usually offer fixed rate ISAs between 1 and 5 years.
  3. Stocks and Shares ISAs: You may find these ISAs appealing, as they can be used as a vehicle for stocks and shares; they give you the opportunity to receive tax-free returns from your investment.
  4. Lifetime ISAs: These may be appealing to those who are looking to save for a deposit for a house or for retirement. What makes lifetime ISAs unique is that the government will add a 25% bonus, up to £1,000, to your initially invested capital.
  5. Junior ISAs: If you want to open an ISA for anyone under the age of 18, then you could explore junior ISAs. These ISAs are specifically designed for anyone under the age of 18. However, it should be noted that all junior ISAs have a smaller tax-free interest ceiling.

18 month fixed rate ISAs

If you are willing to leave your capital in an ISA for 18 months, then an 18 month fixed rate ISA could be a good option for you. An 18 month fixed rate ISA is a rare ISA, but there are some UK high street banks that will provide this mid-term fixed rate ISA.

Some of the best fixed rate ISAs can be found in our table above.

18 month fixed rate ISA features

Although 18 month fixed rate ISAs are not as common as other fixed rate ISAs, the ones on the market will tend to offer similar features.

Qualifying for an ISA...

To qualify for any 18 month fixed rate ISA, you must be over the age of 18 and live in the United Kingdom.

If you are living outside the UK, you may still be able to open an 18 month fixed rate ISA, providing you are a Crown servant (for example a part of the armed forces, a diplomat or overseas civil servant).

Tax-free limit...

An 18 month fixed rate ISA gives your capital the opportunity to receive 18 months’ worth of tax-free interest. The tax-free interest ceiling is reviewed every year. The current ISA allowance is £20,000, and the government will likely decide not to increase it for the next tax year.

The allowance cannot be 'saved up' or carried over into the next tax year. Therefore, it is integral to take full advantage of your tax allowance, as once it is gone it’s gone.

In addition, the tax-free limit is allocated to each individual, and if you open multiple ISA accounts, your ISA allowance will be split between your accounts.

Higher interest...

18 month fixed rate ISAs will usually have better interest rates than 1 year fixed rate ISAs or regular ISAs. Therefore, providing you do not make a withdrawal throughout the 18 month period, you could see your capital grow quickly.


It is vital that you are confident that you will not require your capital throughout the term with an 18 month fixed rate ISA, as ISA providers will not allow you to touch your capital once you have made your deposit.


18 month fixed rate ISA providers typically prohibit withdrawals. However, there are some banks that are willing to allow a grace period or ‘cooling off period’ at the start of the fixed term. ISA providers that have a ‘cooling off period’ will often allow you to withdraw your capital within an agreed timeframe, which is generally 14 days.


Not every 18 month fixed rate ISA will offer a ‘cooling off period’, in fact the majority of ISA providers will levy an early withdrawal fee/ early closure charge in the event a withdrawal is made before the conclusion of the fixed term.

Early withdrawal fees and early closure charges may reduce your capital substantially, as they are often a number of days’ worth of interest.

Minimum deposit...

It is not rare for an 18 month fixed rate ISA provider to require a minimum deposit. Typically, the minimum deposit for an 18 month fixed rate ISA will be between £100 and £2,000; minimum deposits will vary from provider to provider.

If the minimum deposit is large, but you are prepared to leave your capital untouched for 18 months, then opening an 18 month fixed rate ISA may still be worth it for the higher tax-free interest.

Who can open an ISA

To open an 18 month fixed rate ISA you must be over the age of 18 and living in the UK.

If you are looking to open an ISA for someone under the age of 18, then you could open an 18 month fixed rate year junior ISA; these are not as common as other types of ISAs.

Who can contribute to an ISA

Although terms surrounding deposits will depend on the ISA provider, it is rare that there will be any restrictions in relation to who contributes to your ISA. This means that parents, extended family members or even friends can add to your ISA to help your capital grow.

Financial Services Compensation Scheme

The Financial Services Compensation Scheme (FSCS) guarantees the return of up to £85,000 per person, providing the capital is in an account with an authorised UK bank or building society.

The extent of the FSCS's protection will depend heavily on how many ISAs you have and how much capital you have in them.

FSCS protection for an 18 month fixed rate ISA...

FSCS protection extends to an 18 month fixed rate ISA, providing the ISA is with an authorised UK bank or building society; your initial £85,000 will be protected and returned if your ISA provider collapses.

If you have opened multiple ISAs with different banking brands, you should double check that they do not share the same banking authorisation. This is because some banking brands are under the umbrella of the same banking authorisation.

If you have more than £85,000 in an 18 month fixed rate ISA in the same bank (or multiple banks under the same authorisation), you may want to transfer the excess to another bank with a separate authorisation to ensure your capital is fully protected by the FSCS.

Consider the following

The best fixed rate ISA deals are displayed in our ISA table above. By using our table above, you can effectively compare the ISA deals on offer and find the best deal for your financial needs.

When comparing the ISA deals in our table, you may want to consider the following:

Minimum ISA deposits: Find out how much you have to deposit. The majority of 18 month fixed rate ISA providers will have a minimum deposit to open an ISA. You need to consider whether you will need your capital in the near future, can afford the minimum deposit and will the minimum deposit take you over your tax-free ISA allowance.

Early closure/ withdrawal penalties: Confirm whether you can access your capital. Most ISA providers that allow you to withdraw from an ISA before the conclusion of the fixed term will levy an early closure/withdrawal charge.

Additional bonus rewards: Read the small print. There are banks that offer special rewards to entice customers to open an 18 month fixed rate ISA; however, they will usually reduce their interest after the reward has been paid. If you choose an ISA with a special bonus, you may want to be prepared to switch to another ISA provider after the initial period ends.

How the interest is calculated: Not every ISA provider will calculate and pay interest in the same way. For example some ISA providers will offer interest payments monthly, quarterly or annually. It may be worth checking how the interest is calculated and how often interest payments are made when choosing an ISA. 

High Income ISAs

High income ISA ideas:

ISAs Products

Cash ISAs

Fixed Rate & Instant Access ISAs:

Cash ISAs: 

Stocks & Shares ISAs

Types of Stocks and Shares ISA include: 

Stocks and Shares ISAs

Latest News

5 Considerations for Your Next Investment ISA

15th March 2021

You've decided to invest your savings into a Stocks and Shares ISA. You'll be using your tax-free ISA allowance for this year before the deadline, while also investing your money for your future. But what do you need to consider before opening an account? We've put together a list of our top five considerations for you to think about before you click "apply". 

Newsletter Signup

Sign up to our Newsletter to get exclusive news and offers direct to your inbox.

About us is a trading style of Fair Investment Company.

We've been comparing and recommending ISAs for many years so you can trust you're in good hands.

About us

4.74 Average

23 Reviews


I found the way the different options are presented very clear - much more useful than some other comparison sites. I sent it to my daughter as well.


Very informative, find myself a good ISA account with best return in terms of interest.


Easy to use website and up to date. Saved the link on my tablet.

Rob Holden

The website was very useful and informative.

Andrew Johnson

ISA can be confusing at first and this site includes a useful and helpful introduction into the world of ISAs