Post Office Fixed Rate Cash ISA is provided by OneFamily, savings in Post Office Cash ISAs are deposited with Bank of Ireland UK
Easy to set up
All you need to open your Fixed Rate Cash ISA is single deposit of £500 or more, up to £20,000 in the 2026/27 tax year. Additional deposits are not permitted during the term.
Transfer in from other ISAs
You can transfer in ISAs held with other providers (minimum £500). Before making a decision to transfer your ISA to us, you should check if your current provider will charge a fee.
Know how much your savings will earn
The interest rate on this ISA is fixed for the term you choose, so you’ll know just how hard your money will work for you.
Account name: Post Office Fixed Rate Cash ISA (Issue 50)
You must read all tabs of the summary box carefully before applying
| 1 year | 2 year | |
|---|---|---|
| Fixed Rate Cash ISA interest rate | 3.50% Tax Free/AER fixed |
3.45% Tax Free/AER fixed |
| Current variable interest rate - paid after maturity | 0.90% Tax Free/AER variable |
|
For Fixed Rate accounts, interest is calculated daily and paid on the anniversary of the account opening. After the fixed term has ended, interest is paid annually on 20th March
The interest rate of your Fixed Rate Cash ISA is fixed until it reaches maturity.
At the end of the fixed rate, your ISA will earn a variable interest rate. We have the right to change the variable interest rate. The reasons we may change your rate are outlined in the ‘Interest Section’ of the ISA key information.
If we change your interest rate to your disadvantage, we’ll personally notify you a minimum of 14 days before the change takes effect, as long as you have at least £100 in your account.
| After 12 months | £1,035.00 | N/A |
|---|---|---|
| After 24 months | N/A | £1,070.19 |
This projection is based on an annual interest being paid into the ISA (compound interest), and doesn't take into account your individual circumstances.
This assumption is based on a £1,000 deposit with no further deposits or withdrawals during the fixed term of the projection.
As our Fixed Rate Cash ISA is a fixed term product you won’t be able to switch to another product until the end of the fixed term. If you wish to switch into this ISA, please apply in a Post Office branch.
Before making a decision to transfer your ISA to us, you should check if your current provider will charge a fee.
This ISA doesn’t have flexible features. This means that once withdrawn, your money will lose the tax advantages of ISAs and cannot be replaced within this ISA.
If you close your ISA, your money will no longer benefit from the tax advantages of ISAs in the future.
If you’d like to cancel, you can do so within 14 days from the date your Fixed Rate Cash ISA is opened by writing to us. You won’t have to pay a breakage charge if you cancel your account within the 14-day cancellation period.
Interest is paid gross without tax deducted on our Fixed Rate Cash ISA. The tax advantages of cash ISAs depend on your individual circumstances, and the tax treatment may change in the future.
Please read these documents and guides before you apply. You may like to save or print them for future reference.
Complete an application form and send it to us in the post. By applying you confirm that you have read and understood all sections of the summary box and key documents for this product.
Anyone over the age of 18 years who’s a UK resident can open a Fixed Rate Cash ISA with a lump sum investment minimum of £500 and maximum of £20,000 deposit (subject to contributions in other types of ISAs).
Alternatively transfers-in from an ISA held with another provider (minimum £500) are accepted. Before transferring your ISA to us, you should check if your current provider will charge a fee.
We can open an account as soon as we receive a valid application and your initial payment. To do this, we need to confirm your identity and address. Some customers may be required to provide further evidence, and in these cases, we’ll write to you.
Please note, interest is payable on your Fixed Rate Cash ISA once your account has been opened and your initial payment has been accepted.
AER:
AER stands for Annual Equivalent Rate and shows what the interest rate would be if interest was paid and added to your account each year.
Variable:
A variable rate of interest can go up or down throughout the lifetime of a savings account.
Fixed:
A fixed rate of interest remains the same and doesn't change for the duration of the term.
Tax-free:
Tax-free means the interest paid will be free from UK Income Tax and Capital Gains Tax. The tax advantages depend on your individual circumstances and the tax treatment of your ISA may change in the future.
Gross:
Gross rates means we will not automatically deduct tax from the interest we pay on money in your account. It’s your responsibility to pay any tax you may owe to HM Revenue & Customs (HMRC).
Nominated Account:
A Nominated Account is a current account that we link to your savings account so that you can transfer money safely and securely. It must be a UK personal bank or building society account in your name(s) that accepts Direct Credits.
Breakage charge:
A charge applied if you close or transfer your account, or your account or any deposits are voided, within the fixed rate term.
Please note: The tax advantages of ISAs depend on your individual circumstances and the tax treatment of ISAs may change in the future.
Find out more about the Financial Services Compensation Scheme (FSCS) and how it protects your savings.
Post Office Fixed Rate Cash ISA is provided OneFamily, savings in Post Office Cash ISAs are deposited with Bank of Ireland UK.
OneFamily is a trading name of Family Assurance Friendly Society Limited (incorporated under the Friendly Societies Act 1992, Reg. No. 939F), of which Family Equity Plan Limited (Co. No. 2208249) is a subsidiary. Financial Services Register numbers 110067 and 122351 respectively. Registered in England and Wales at 16-17 West Street, Brighton, BN1 2RL, United Kingdom. Family Assurance Friendly Society Limited is authorised by the Prudential Regulation Authority and regulated by the Financial Conduct Authority and the Prudential Regulation Authority. Family Equity Plan Limited is authorised and regulated by the Financial Conduct Authority.
Bank of Ireland UK is a trading name of Bank of Ireland (UK) plc which is authorised by the Prudential Regulation Authority and regulated by the Financial Conduct Authority and the Prudential Regulation Authority under registration number 512956. Registered in England and Wales (No. 07022885). Registered Office: 45 Gresham Street, London EC2V 7EH.
The above details can be checked on the Financial Services Register by visiting the Financial Conduct Authority website.
Post Office Limited is registered in England and Wales (No. 2154540). Registered Office: 100 Wood Street, London, EC2V 7ER. Post Office and the Post Office logo are registered trademarks of Post Office Limited.
Rates correct as of 23rd January 2026.