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18 Month Fixed Rate ISA Accounts

If you normally deposit your whole cash ISA allowance in one go, and don’t make any withdrawals during the tax year, a 18 month fixed rate ISA could be the best route for you. Paying a guaranteed rate of interest, a fixed ISA can help you maximise your returns in comparison to easy access accounts. View today's best rates below.

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Browse Fixed Rate ISA Terms

Best 18 Month Year Fixed Rate ISAs

Best 18 Month Year Fixed Rate ISAs

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  • Cumberland BS 18 Month Fixed Cash ISA
    AER
    5.10%
    Account Type
    Cash ISA
    Term
    24.06.25
    Interest Paid
    Yearly
  • Newcastle BS 18 Month Fixed Rate ISA (Issue 20)
    AER
    5.10%
    Account Type
    Cash ISA
    Term
    23.06.25
    Interest Paid
    Yearly
    Further Options ˅
    AER
    5.10%
    Account Type
    Cash ISA
    Term
    23.06.25
    Interest Paid
    Monthly
  • Barclays Bank 18-Month Flexible Cash ISA - Issue 52
    AER
    5.05%
    Account Type
    Cash ISA
    Term
    18 Month Bond
    Interest Paid
    On Maturity (Compounded Annually)
    Further Options ˅
    AER
    5.05%
    Account Type
    Cash ISA
    Term
    18 Month Bond
    Interest Paid
    Monthly
  • Monmouthshire BS 18 Month Fixed Rate ISA - Issue 5
    AER
    5.00%
    Account Type
    Cash ISA
    Term
    18 Month Bond
    Interest Paid
    Anniversary
  • Darlington BS 18 Month Fixed Rate Cash ISA (74)
    AER
    4.95%
    Account Type
    Cash ISA
    Term
    30.04.25
    Interest Paid
    Yearly
  • TSB 18 Month Fixed Rate Cash ISA
    AER
    4.75%
    Account Type
    Cash ISA
    Term
    18 Month Bond
    Interest Paid
    Monthly
  • Gatehouse Bank 18 Month Fixed Term Woodland Cash ISA
    AER
    4.70%
    Expected Rate
    Account Type
    Cash ISA
    Term
    18 Month Bond
    Interest Paid
    On Maturity
    Further Options ˅
    AER
    4.70%
    Expected Rate
    Account Type
    Cash ISA
    Term
    18 Month Bond
    Interest Paid
    Monthly
Depositor Protection

Eligible deposits with UK institutions are protected by the Financial Services Compensation Scheme (FSCS) up to a maximum level of protection of £85,000 per person per institution. All new savings or bank accounts provided to UK customers are now covered by the FSCS.

Disclaimer

All rates subject to change without notice. Please check all rates and terms before investing or borrowing.

Provider Links

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A guide to 18-month fixed rate ISAs

At a glance

  • 18-month ISAs are the perfect halfway house between one and two-year accounts.
  • The interest rate will be fixed for 18 months so returns are guaranteed and, as with all ISAs, any interest earned is tax-free.
  • Make sure you can commit to the full term, as early access will usually result in a penalty.

What is an 18-month fixed rate ISA?

An 18-month fixed rate ISA asks you to lock away a lump sum of money for 18 months, with the promise of a guaranteed return at the end of it. Rates will normally be higher than for one-year and variable rate ISAs and any interest will be tax-free, though you’ll have limited flexibility and won’t be able to access your funds without paying a penalty.

Who are 18-month ISAs most suitable for?

An 18-month ISA will be ideal for those who have a specific short-term savings goal, or who want to receive a decent rate of interest without losing access for years on end. They can be just as suitable for savers who want to avoid the possibility of rates falling in the near-future, while still enjoying all the benefits of an ISA.

What should I look out for in an 18-month ISA?

The rate will be the most important aspect to consider in an 18-month ISA, but it certainly isn’t the only thing to think about. Other factors to bear in mind include:

  • Transfer options. If you’re considering transferring previous years’ ISA savings, make sure that the account you’re looking at accepts transfers. Be mindful that some accounts will accept transfers of cash ISAs but not stocks and shares, for example, so always read the small print.
  • Funding requirements. Different accounts will have different minimum funding requirements, so make sure yours is suitable for the amount you want to invest. Remember that these accounts are suited only to lump sum savings; further additions will rarely be possible, and if so will normally only be allowed for a short period, so don’t expect to be able to add to the account repeatedly during the term.
  • Access restrictions. All fixed rate ISAs will have some form of access restriction and 18-month versions are no exception, but as per ISA rules, you should be able to access your money if you need. Just make sure to check the penalty for doing so – loss of interest penalties are common, and some providers will expect you to close your account as well.
  • Account management options. These days online and app-based account management is becoming far more popular, particularly among challenger providers. Given that the best 18-month ISAs will typically be offered by these smaller banks, make sure you’re comfortable with opening and operating an account in this way.

Looking for the best 18-month fixed rate ISAs?

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Download our complete guide to the ISA allowance for 2023/24. Restrictions, how to move accounts and taxation considerations.

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Moneyfactscompare.co.uk will never contact you by phone to sell you any financial product. Any calls like this are not from Moneyfacts. Emails sent by Moneyfactscompare.co.uk will always be from news@moneyfacts-news.co.uk. Be ScamSmart.

Moneyfactscompare.co.uk will never contact you by phone to sell you any financial product. Any calls like this are not from Moneyfacts. Emails sent by Moneyfactscompare.co.uk will always be from news@moneyfacts-news.co.uk. Be ScamSmart.