Each tax year, there’s a limit to how much you can pay into ISAs while keeping your returns tax-free - this is known as your ISA allowance.
The allowance for this tax year (2025/26) is £20,000. The tax year runs from 6th April to 5th April each year.
This means you can invest up to £20,000 across all your ISAs combined, without paying tax on any income or gains.
What counts towards the allowance?
- Any new money you add to your ISA during the tax year
- Contributions across all your ISA types, including:
- Stocks & Shares ISAs
- Cash ISAs
- Lifetime ISAs (LISAs) (Maximum £4,000)
- Innovative Finance ISAs
ISA transfers from another provider don’t use up your allowance — as long as they’re completed correctly. Any gains made from the money added to your ISA also do not use up your allowance.
Check out our step-by-step guide to transferring ISAs for more information.
You can now subscribe to more than one Stocks & Shares ISA per year
Since April 2024, you can subscribe to more than one Stocks & Shares ISA in the same tax year, across different providers - as long as your combined total stays within the £20,000 allowance.
For example, you could invest £12,000 with InvestEngine and £8,000 with another provider.
A quick reminder: it’s your responsibility to make sure you don’t go over the limit.
If you do, you’ll need to contact HMRC to resolve this, and they may require you to withdraw the excess.
You can read the full rules on the HMRC ISA guidance page.
What about withdrawals?
If you have a Flexible ISA (like InvestEngine’s), you can withdraw money and replace it within the same tax year without affecting your £20,000 allowance.
Read more about Flexible ISAs here
When does the tax year run?
- From 6 April to 5 April each year
- Your ISA allowance resets on 6 April
- You can’t carry over any unused allowance — it’s “use it or lose it”
Where can I check my remaining allowance?
You’ll see your remaining ISA allowance clearly in your Dashboard, above your ISA portfolios. It’s also shown whenever you add or withdraw money.
If you’ve withdrawn funds and plan to replace them, we’ll show you how much you can still deposit under the flexible rules.
ISA voiding: correcting excess contributions
If you’ve accidentally exceeded your ISA allowance, it’s important to address this as soon as possible to ensure your account remains compliant with HMRC rules.
What happens if I go over my ISA allowance?
The next steps depend on when the excess contribution was made.
If the excess deposit was made in the current tax year, you do not need to contact HMRC. Our team can arrange for the excess contribution to be voided in line with HMRC requirements.
If the excess relates to a previous tax year, you may need to contact HMRC directly. Our team will review your case and confirm the appropriate next steps.
When processing a void, we will calculate the total amount that needs to be removed from the ISA to ensure it complies with HMRC rules. This may include any investment growth associated with the excess contribution.
If your funds have already been invested, you may need to sell sufficient assets to allow the correction to be completed. We will confirm the required amount before any action is taken.
If you believe you may have exceeded your ISA allowance, please contact our Client Support team as soon as possible so we can help resolve the issue quickly and correctly.
ISA voiding: Why staying within the rules matters
It’s important to stick to the ISA rules — especially around contribution limits and account eligibility. If you exceed the annual ISA allowance or break HMRC guidelines (for example, by exceeding the total allowance across multiple Stocks & Shares ISAs), your ISA may be declared void.
A void ISA loses its tax-free status, meaning:
- You may have to pay tax on any gains or income
- HMRC may require you to correct the mistake, which can be time-consuming
- The funds may need to be removed or reallocated
If you’re unsure about your contributions across providers, or your eligibility, it’s always worth checking with HMRC or seeking tax advice before continuing.
Ready to get started?
Opening an ISA portfolio with InvestEngine takes just a few minutes — and you’ll be using your allowance in the most tax-efficient way possible.
Check out our guide to get started here
When investing your capital is at risk, your investments may go up or down.