Earn 3.50% interest
Tax-free/AER (Fixed) guaranteed rate for 18 months.
18 Month Fixed Rate Cash ISA
18 Month fixed term
Deposit your money within 30 days of opening the account.
Withdrawals allowed. Charges apply.
You’ll be charged based on the term and amount withdrawn.
Earn tax-free interest
Interest paid monthly and on maturity. Interest earned doesn’t count towards your personal savings allowance. Please read the summary box below before applying.
| Term | Interest rate |
|---|---|
| 18 Month | 3.44% Tax free/3.50% AER (fixed) |
Interest is calculated each day. Interest is paid monthly and at maturity.
No, we can't change the interest rate during the fixed term of your Fixed Rate Cash ISA.
| Initial deposit | £3,000 |
|
| Fixed Rate Cash ISA - 18 Months | Interest earned at 3.44% Tax free/3.50% AER (fixed) | £158.89 |
| Estimated balance after 18 months | £3,158.89 |
This is an example only and doesn't take into account your individual circumstances.
Ways to open |
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| Who can open | You must be:
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| Open with |
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| Manage your account |
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Withdrawals allowed: Yes
Notice Period: None
Withdrawal charges: Yes
If you take money out of your account more than 14 days after opening the account, you'll pay a charge. This includes transfers to another ISA with us or to another provider. The charge depends on the term of your account:
| Term | Withdrawal charge |
|---|---|
| 18 Month | Equivalent to 135 days' interest on the amount taken out or transferred |
For example: if you had an account with an 18 month term and took out £2,000, the charge would be the amount of interest you’d earn on the £2,000 for 135 days.
We’ll take the charge from the balance in your account before you take out the money. You may get back less money than you originally paid into your account.
How to Withdraw:
- Cash
- Bankers draft
- Transfer to TSB current or savings account
(Fees may apply, see our Savings Account General Conditions for more information)
You can withdraw and replace money from your Fixed Rate Cash ISA without it counting towards your yearly ISA allowance for that year, as long as the repayment is made in the same tax year as the withdrawal, and paid into a new Fixed Rate Cash ISA or Cash ISA Saver.
- Accounts can only be opened in a sole name.
- Opening a Fixed Rate Cash ISA will limit the amount that can be invested in a stocks and shares or innovative finance ISA. To find out more about this, speak to a Partner in your local branch or call us.
- The tax advantages depend on your individual circumstances and the tax treatment of your ISA may change in the future.
- Your account will mature into a Cash ISA Saver (off bonus) at the end of the term. We'll contact you before this happens with your options.
- If you aren't happy with your Fixed Rate Cash ISA, you can cancel within 14 days without charge.
- You can also close your account after 14 days subject to the charge above.
Rates and information correct as at 21/11/2025.
The Annual Equivalent Rate (AER) shows what the interest would be if the interest was paid and added to the account once each year. It lets you compare savings accounts easily. Gross rate is the contractual rate of interest payable before the deduction of income tax. Tax free is the contractual rate of interest payable where interest is exempt from income tax. Tax treatment depends on your individual circumstances and may change.
Apply for a 18 Month Fixed Rate Cash ISA
New to TSB?
Register and apply for your Fixed Rate Cash ISA
You must be 18 or over and a UK resident to apply
Apply for a 18 Month Fixed Rate Cash ISA
Already a TSB customer?
You’ll need to be registered for Internet Banking to apply
You must be 18 or over and a UK resident to apply
If you prefer to apply in branch or through telephone banking, you can book an appointment in advance.
Important documents
Fixed Rate Cash ISA FAQs
We’ll let you know a few months before your ISA fixed term is coming to an end.
- On maturity your Fixed Rate ISA will mature into a Cash ISA Saver without bonus.
- We will notify you when your ISA fixed term is coming to an end, so you re always in control.
- Manage your Savings account online with our mobile app and Internet Banking.
Find out more information on your savings account maturity options here.
Important Information
The Annual Equivalent Rate (AER) shows what the interest would be if the interest was paid and added to the account once each year. It lets you compare savings accounts easily. Gross rate means that credit interest is paid without income tax being deducted. Tax-free is the contractual rate of interest payable where interest is exempt from income tax.
Tax-free means the interest paid will be free from UK Income Tax. The tax advantages depend on your individual circumstances and the tax treatment of your ISA may change in the future. You need to be 16+ and UK resident to open most of our savings accounts with the exception of Savings Pots and TSB ISAs. For children under 16 please see specific pages for opening procedures
