Earn tax-free interest with a Fixed Rate Cash ISA
Lock in a great rate and grow your savings tax-free — with terms from 12 to 36 months.
ISA applications for the 2025/26 tax year need to be submitted by 12pm on Tuesday 31 March 2026. Applications for the 2026/27 tax year will open in the new tax year. If you’re looking to top up an existing ISA, electronic payments must reach your account by 5pm on Thursday 2 April 2026, and cheque payments by Wednesday 1 April 2026 to count towards the 2025/26 ISA allowance. Any money received after the cut-off will count towards your 2026/27 ISA allowance.
A Fixed Rate Cash ISA is a tax-free individual savings account, which means you won’t pay any tax on the interest that you earn.
You can save up to £20,000 into one Cash ISA in a tax year. With an OakNorth Fixed Rate Cash ISA, you’ll earn a set interest rate throughout, so you’ll know what your returns are upfront – and they won’t change. So, if you’re looking to make your money go further, see our range of ISAs with terms from 12 to 36 months.
Enjoy tax-free growth on your interest. Save up to £20,000 in any one tax year.
No teaser rates, no gimmicks. Just fixed interest that rewards your goals.
Start saving from as little as £1. Pick the term that works for you — 12, 24 or 36 months.
Use our calculator to find out how much interest you could earn and what your savings might be worth at the end of your term.*
A Fixed Rate Cash ISA means putting away your savings to earn competitive interest rates and avoid penalty fees. Although we allow you to withdraw your money at any time, this comes with a penalty – equivalent to an interest reduction. So, if you think you’ll need regular access to your savings an Easy Access Cash ISA may be a better fit for you.
Watch your savings grow with a return that makes a difference.
No paperwork, no phone calls — just a few taps to start saving.
Track your savings from the app or your online account and stay in control.
FSCS-protected up to £120,000. Your savings are in safe hands.
A Fixed Rate Cash ISA works similarly to a Fixed Term account — your money is locked away for an agreed period, but you can still access it if needed. Just keep in mind that withdrawing early comes with a penalty.
If you withdraw before the end of your term, you’ll lose 90 days’ interest on a 12-month term, 180 days’ interest on a 24-month term or 270 days’ interest on a 36-month term. So it’s important to choose a term that suits your needs and access preferences.
Here’s how it works in 3 simple steps:
Choose the Fixed Rate Cash ISA that works for you — available in 12, 24, or 36-month terms.
Fill in a quick application on our website or via the OakNorth app with just a few personal details.
Start earning tax-free interest. Remember, early withdrawals reduce the interest earned.
Since 2015, our lending has helped create 56,000 new homes and 34,000 jobs, driving real impact across the UK. We’re committed to sustainability, targeting net zero across all emissions by 2035, including those we finance. Through our 1+1% Commitment, we donate 1% of group profits and 1% of our team’s time to charitable initiatives, helping communities thrive while your savings grow.
If you’re over 18 years old and you’re a resident of the UK – i.e. you have a permanent UK address that you’ve had for over three years – then you’re eligible for an OakNorth fixed rate cash ISA. You’ll also need to have a personal UK bank or building society account to transfer funds into your account.
ISAs are individual savings, so we don’t offer joint ISA products.
No, your interest rate will remain the same throughout the duration of your fixed term ISA.
*This calculator provides an illustrative estimate of how your savings could grow over time based on the information you enter. The estimate assumes that the interest rate does not change during the period, that any contributions are made on the [1st of the month] and no withdrawals are made. The estimate does not account for tax, fees, or future rate changes. Actual returns may vary depending on your account type, deposit amount, term, and tax status. This information does not constitute financial advice or a recommendation, and OakNorth Bank accepts no responsibility for any losses arising from reliance on these calculations.
