What Happens to Your ISA on 5 April?
The UK tax year runs from 6 April to 5 April the following year. For ISA purposes, 5 April marks the end of the period in which contributions are counted towards that tax year’s annual ISA allowance.
When the new tax year begins on 6 April, a new annual ISA allowance becomes available under the rules applying to that year.
What does not happen is a reset of the ISA itself.
Money or investments already held inside your ISA can normally remain there. You do not have to withdraw them, and an existing ISA does not normally close simply because the tax year has ended.
This means there are three separate things to understand at the tax-year boundary:
Your existing ISA balance can remain.
Unused allowance from the old tax year generally expires.
A new annual allowance becomes available for qualifying new contributions.
Keeping those three ideas separate makes the ISA tax-year rules much easier to understand.
If you want to explore the contribution limit itself in more detail, ISA Allowance Explained explains how the annual allowance works.
Does Your Existing ISA Balance Count Towards the New Allowance?
No. Money already accumulated inside an ISA does not become a new contribution simply because 6 April arrives.
Suppose you have £25,000 inside an ISA on 5 April. That balance might have been built from contributions made over several tax years, together with interest, investment income or investment growth generated inside the account.
When the new tax year begins, the £25,000 can normally remain within the ISA.
It is not treated as though you have suddenly contributed £25,000 during the new tax year, so simply carrying that balance forward does not use £25,000 of the new annual allowance.
This distinction explains why the value held within an ISA can eventually become much larger than the amount that can be contributed during a single tax year.
Your ISA balance and your annual ISA allowance measure different things.
The balance is the value already held within the ISA. The annual allowance governs qualifying new contributions made during a particular tax year.
Interest or investment growth generated by money already inside the ISA does not itself become a new contribution either.
The simplest way to remember the distinction is:
Your accumulated ISA balance carries forward. Your allowance for new contributions operates by tax year.
What Happens to Unused ISA Allowance?
Unused ISA allowance generally does not carry forward into a later tax year.
Suppose you reach 5 April with £5,000 of that tax year’s ISA allowance still unused. When the tax year ends, that £5,000 does not become additional allowance that can be added to the allowance available from 6 April.
Instead, the old tax year’s unused allowance generally expires and the new tax year begins with the annual allowance applying to that year.
This is different from the money already inside your ISA. Existing ISA money can remain within the wrapper across multiple tax years, while unused annual allowance generally cannot be carried forward.
There is also no requirement to use your entire ISA allowance before 5 April.
An ISA allowance is a maximum contribution limit, not a savings or investment target. Having allowance remaining at the end of the tax year does not by itself mean that you need to make another contribution.
Whether money is saved, invested or kept available for another purpose is a separate financial decision from whether ISA allowance remains available.
The tax-year rule simply determines how much can be contributed under the ISA rules and which tax year a qualifying contribution belongs to.
What Changes When the New Tax Year Begins?
The transition from 5 April to 6 April affects the allowance for new contributions rather than resetting money already accumulated inside your ISA.
What Changes When the New Tax Year Begins?
The tax-year boundary changes the allowance available for new ISA contributions rather than resetting the money already held inside your ISA.
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Your existing ISA balance remains
Money and investments already held within your ISA can normally remain there. Previous contributions and eligible returns do not become new contributions when 6 April arrives.
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Unused old allowance expires
Any annual ISA allowance you have not used by the end of 5 April generally cannot be carried forward into the new tax year.
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A new allowance becomes available
From 6 April, qualifying new ISA contributions are considered against the annual allowance applying to the new tax year.
Your ISA balance can build across many tax years. It is the allowance for making new contributions that operates separately for each tax year.
For example, someone could have accumulated a substantial ISA balance over several years while making further contributions each year.
The existing balance does not have to be removed and paid back in every April. It can remain inside the ISA while new contributions are considered separately under the rules for the new tax year.
This separation between existing ISA money and new ISA contributions is the central principle behind what happens at the end of the tax year.
Can You Keep Paying Into the Same ISA?
In many cases, yes.
You do not automatically need to open a new ISA simply because a new tax year has begun. If your existing ISA remains open and accepts further contributions, you may be able to continue paying into it after 6 April.
Qualifying new contributions are then considered under the ISA rules and allowance applying to the new tax year.
The account’s own terms still matter, however. An individual ISA product might have restrictions on additional deposits, a maturity date or other conditions affecting whether further money can be added.
The start of a new tax year therefore gives you a new annual allowance, but it does not guarantee that every existing ISA product will continue accepting new contributions indefinitely.
There is also no requirement to withdraw existing ISA money simply because you want to use a different ISA or provider.
If you want to move existing ISA savings or investments while preserving their ISA status, the formal ISA transfer process is normally relevant. Withdrawing the money yourself and paying it into another ISA can be treated differently.
How ISA Transfers Work explains the transfer process and how it differs from making a new ISA contribution.
What If You Contributed Too Much Before 5 April?
The beginning of a new tax year does not automatically correct an excess ISA contribution made during the previous tax year.
If a contribution exceeded what was permitted under the ISA rules before 5 April, that contribution still relates to the tax year in which it was made.
The arrival of a new annual allowance on 6 April does not simply move the earlier excess into the new tax year.
This is different from legitimately using all of your available ISA allowance. The issue arises where contributions have gone beyond what was permitted under the applicable rules.
If you think you may have exceeded your ISA allowance, avoid assuming that withdrawing the excess yourself will necessarily correct the position. How an excess subscription is dealt with can depend on the circumstances and the applicable ISA correction rules.
What Happens If You Exceed Your ISA Allowance? explains this situation in more detail.
The important principle for the tax-year boundary is that a new allowance applies to the new tax year; it does not retrospectively change contributions made during the previous one.
Why Does the 5 April ISA Deadline Matter?
The practical importance of 5 April is that it determines which tax year’s allowance a contribution uses.
If you make a qualifying ISA contribution before the end of 5 April, it is considered within the tax year that is about to end.
A qualifying contribution made from 6 April instead falls within the new tax year and is considered against the allowance applying to that year.
This can matter when you have already decided to contribute money to an ISA because unused allowance from the old tax year generally cannot be carried forward.
However, the approaching deadline does not by itself mean that making an ISA contribution is necessary.
Unused ISA allowance is not money that you lose. It is simply contribution capacity that expires.
Money might instead be needed for everyday spending, an emergency fund, upcoming expenses or another purpose. Similarly, the availability of ISA allowance is not by itself a reason to invest money or accept investment risk.
The deadline therefore has a specific meaning:
If you have already decided to make an ISA contribution, the date on which it is made determines which tax year’s allowance it uses.
That is different from saying that everyone should try to use their full allowance before 5 April.
Conclusion
The end of the tax year changes your ISA allowance, not the money already accumulated inside your ISA.
When 5 April ends, unused allowance from that tax year generally expires. From 6 April, a new annual allowance becomes available for qualifying new contributions.
Your existing ISA balance can normally continue across that boundary. Previous contributions, interest and investment growth do not suddenly become new contributions simply because a new tax year has begun.
You also do not automatically need to open a new ISA each April, although whether you can continue contributing to a particular account depends on its terms.
The key distinction is therefore straightforward:
Your ISA can continue from one tax year to the next. It is the annual allowance for new contributions that starts again with the new tax year.
