5 Year Fixed Rate Cash ISA Monthly Interest

Our 5 Year Fixed Rate Cash ISA may be right for you if you have a lump sum to pay in and you don't need to take your money out for five years.


  Interest rate Balance Tax-free^ each year AER†
Annual interest £500 - £20,000 4.00% 4.00%
Monthly interest £500 - £20,000 3.93% 4.00%
  • Open this ISA in branch, at an agency or online
  • Pay in from £500 to £20,000 in the current tax year
  • You can only pay your ISA Allowance into one Principality Cash ISA in the current tax year.
  • Transfer in existing ISAs by completing a form via post or in branch. ISA funds need to be available to be transferred within 5 business days of your request

  • Add more money to the ISA until it is taken off sale
  • Choose to have the interest paid once a year or every month
  • No withdrawals allowed before the end of the five-year term 
  • If you close or transfer the ISA early you must give up 360 days' interest
  • We can stop accepting applications at any time

  Summary Box
What is the interest rate? Fixed annual interest      4.00% Tax-free^ each year      4.00% AER†
Fixed monthly interest    3.93% Tax-free^ each year      4.00% AER†

(See the meanings of ‘Tax-free’ and ‘AER’ at the bottom of the page)

Interest is calculated each day on the money in the account and paid:
  • annually (each year), on each anniversary of your ISA opening; or
  • monthly, starting one month after the date your ISA is opened, and then each month after that;
    whichever you choose.
  • Can Principality change the interest rate? No, the rate is fixed for five years until the ISA matures (when the account comes to an end).
    What would the estimated balance be after 60 months based on a £1,000 deposit? £1,216.65

    This is based on you choosing to have interest paid annually and added to your ISA, and not making any further payments into the account.
    How do I open and manage my account?
    • You must be a UK resident and satisfy the minimum age requirements to open a cash ISA (see your 5 Year Fixed Rate Cash ISA account terms).
    • You can open your ISA in branch, at an agency or online. If you want to open this ISA with funds from a Principality fixed term ISA that has matured, you can do this online, in branch, at an agency or by post.
    • You must keep at least £500 (the minimum balance) in the account.
    • You cannot pay in more than than the ISA Allowance each tax year. The ISA Allowance for the current tax year (2024/2025) is £20,000. You can only pay your ISA Allowance into one Principality cash ISA in the current tax year.
    • You can transfer unlimited amounts from ISAs from previous tax years, as these are not part of your current year's ISA allowance.
    • You must make the first payment into your ISA within five business days of it opening. If you don’t, we may close the account.
    • You can keep making payments into your ISA while we are still offering this ISA to customers.
    • Your ISA will mature after 5 years, on the anniversary of the account opening.
    • You can manage the account in branch, at an agency, by post or online through our Your Account service at principality.co.uk.
    Can I withdraw money?
    • No, you cannot make withdrawals from your ISA before it matures.
    • If you close or transfer your ISA before the end of the fixed-rate term (within five years), you will lose 360 days’ interest. If you haven’t earned enough interest to cover the 360 days’ interest it will be taken from the money in the account. This means you may get back less than you originally put in.
    • We will write to you before your ISA matures to find out what you want to do with your money.
    • If we don’t receive any instructions from you before your ISA matures, we will move your money to our Variable Rate Cash ISA or the nearest equivalent we offer at the time.
    Additional information
    • Service charges and costs may apply to your ISA. These are set out in our Tariff of Charges.
    • In certain circumstances we may refuse an instruction for using an account. These circumstances are set out in our Savings Terms and Conditions.
    • The tax treatment of your savings depends on your individual circumstances and may change in the future. This is set by HM Revenue and Customs (HMRC). Further information can be found at gov.uk/individual-savings-accounts/how-isas-work
    • The interest rates quoted above were correct on 18/07/2024.

    Before you apply below, please read the 5 Year Fixed Rate ISA Issue 349 Terms & Conditions

    If you are transferring previous years' ISA subscriptions, please enter your initial deposit as £500 on the application form. The application form will ask you whether you are making a transfer later in the process.

    You can only invest in one Principality Cash ISA per tax year.

    As you will be bound by the account terms of the ISA and your information held in accordance with our privacy policy, you should read, print and save the below documents for your records. If you have any queries relating to them please contact us for further information.

    Please also read the following:

    ^Tax-free means UK Income Tax and Capital Gains Tax is not deducted from the interest you earn. This depends on your individual circumstances, and may change in future.

    †AER stands for Annual Equivalent Rate and illustrates what the interest rate would be if interest were paid once each year on the whole balance, including previous interest payments. 

    • 6th largest UK building society
    • A mutual building society, owned by and run for the benefit of our 500,000 members
    • Over 150 years experience
    • Taking care of over £10 billion of our customers' assets

    We are covered by the FSCS

    Find out more about what it means for you.