Each tax year, your ISA allowance resets - giving you a fresh opportunity to invest tax-free. But timing matters, especially around the tax year-end and when your new allowance becomes available.
This article explains the key cut-off times and start dates to help you make the most of your ISA allowance.
When does the tax year run?
The UK tax year runs from 6 April to 5 April the following year.
You get a new ISA allowance each tax year, and it does not carry over if unused. For 2025/26, the allowance is £20,000.
End-of-year cut-off
To use your ISA allowance for the current tax year, you must:
- Add funds to your ISA portfolio before midnight on 5 April 2026
However, to be safe — especially with bank transfers — we recommend:
- Using Open Banking for faster processing
- Avoiding BACs or late-night transfers near the deadline
If your payment doesn’t arrive in time, it may be counted against next year’s allowance.
When does the new allowance start?
Your new ISA allowance becomes available from 00:01 am on 6 April.
If you’ve already used your full allowance for the previous year, you can continue investing once the new tax year begins — and we’ll automatically track your allowance for the new year.
You’ll see your refreshed allowance on your InvestEngine dashboard.
What happens if I make a withdrawal at year-end?
If you have a Flexible ISA and you withdraw money before 5 April, you must replace it by the same date to preserve your current-year allowance.
If you replace the funds after 5 April, it will count towards your new allowance for the next tax year.
Read more about Flexible ISAs here
How to stay on track
- Log in to your InvestEngine dashboard to see how much ISA allowance you’ve used or have remaining
- We update your allowance in real time as you add or withdraw money
- If you're planning a year-end top-up, give yourself plenty of time for transfers to clear
Next steps
Want to add to your ISA or get started with a new portfolio?
Read more about making payments or Opening your first ISA portfolio
When investing your capital is at risk, your investments may go up or down