Junior ISA at 16 and 18: What Changes and When
A Junior ISA changes at two ages. From 16 the child can become the registered contact and run the account, but gov.uk says money cannot be taken out until 18, apart from the terminal illness and death cases. At 18 the account turns into an adult ISA automatically and the child can take money out.
The site's rules data was last checked against gov.uk on 26 September 2026. Figures typed in this guide may not yet reflect a later change, and the descriptions of gov.uk pages are summaries that may also lag. The current figures are on the ISA rules at a glance page. General information only, not financial advice.
What is a Junior ISA, in brief?
A Junior ISA is a tax-free savings or investment account for a child under 18. A parent or guardian with parental responsibility opens it for a child under 16, and a child aged 16 or over can open their own. The money belongs to the child. gov.uk says anyone can pay money into a Junior ISA, but the total paid in cannot go over the yearly limit of £9,000, across all of that child's Junior ISAs combined.
That limit is shared between account types. If some of it goes into a cash Junior ISA in a tax year, only what is left of the limit can go into a stocks and shares Junior ISA in the same year. As a made-up example, if £2,500 went into the cash account, the stocks and shares account could take payments only up to the remainder of the yearly limit. The rules are set out on the gov.uk Junior ISA page, and our guide to the Junior ISA allowance goes through the limit in more detail.
What happens to a Junior ISA when the child turns 16?
At 16 the child can take over as the registered contact for their Junior ISAs. The registered contact is the person the provider deals with. Until then it is the person with parental responsibility who opened the account, and gov.uk says only the registered contact can manage it: changing the type of account, moving it to another provider, or telling the provider about changes in circumstances.
One point is worth being clear on:
- Taking control is not the same as being able to withdraw. Gov.uk states that you cannot take money out of a Junior ISA until the child turns 18. It lists two exceptions, for a terminally ill child and for a child who has died; see the gov.uk page on a child who is terminally ill or dies.
Can a 16-year-old open an adult ISA?
Gov.uk says you must be 18 or over to open an ISA. It also says you can get a Junior ISA for children under 18, and that a child aged 16 or over can open their own Junior ISA. The gov.uk pages read for this guide say nothing about an adult Cash ISA for a younger person.
If a provider offers a product to a person under 18, it is worth asking the provider which product it is and on what terms. Nothing in this guide should be read as saying either way for a particular provider.
What happens when the child turns 18?
Gov.uk states that Junior ISAs automatically turn into adult ISAs when the child turns 18. At the same point the child can take out any money in the account, since the restriction on withdrawals ends. The account belongs to them already, so there is no transfer of ownership; what changes is that the account now follows adult rules.
Details that the gov.uk pages read for this guide do not spell out, and that are worth asking the provider about, include:
- Whether the adult ISA is the same kind as the Junior ISA was, for example cash or stocks and shares.
- How and when the provider contacts the account holder, and what they need to see.
- What interest rate, charges or investment options apply once the account is an adult ISA.
- What the process is for moving the adult ISA to another provider.
Gov.uk also says that a Junior ISA and an adult ISA cannot be swapped by moving money between them. Whether the normal ISA transfer process applies once the account has become an adult ISA is a question for the provider; our guide to how to transfer ISA accounts explains the general process.
Which allowance counts, and when?
The Junior ISA limit of £9,000 is a separate yearly limit for the child's account. The adult allowance, which is £20,000 in the current tax year (2026-27), is the total that a person aged 18 or over can pay into their own ISAs in a tax year. Gov.uk describes it as the most you can save in ISAs in a year, and you can split it across ISA types.
gov.uk gives the two limits as separate figures, and the pages read do not say whether payments into a child's account affect an adult's allowance, so HMRC or the provider can confirm the position for a particular family. For rules on how the adult allowance is worked out and how it is shared between types, see the site's ISA rules page. The tax year runs from 6 April to 5 April, so the age at which an account changes can fall part-way through a year. How the provider treats payments made in the year of the birthday is worth asking about.
Junior ISA age-by-age table
| Age of child | What the child can do | What the parent or guardian can do |
|---|---|---|
| Under 16 | The money belongs to them. Cannot manage it. Cannot withdraw, apart from the terminal illness and death cases. | Manages the account as registered contact; anyone can pay in up to the yearly limit. |
| 16 up to 18 | Can open their own Junior ISA, or become the registered contact of an existing one, and manage it. Cannot withdraw, apart from the terminal illness and death cases. | Anyone can still pay in, up to the yearly limit. |
| 18 | The account becomes an adult ISA automatically. Can withdraw. Can open ISAs in their own name, since 18 is the minimum age for an adult ISA. | No Junior ISA payments are possible any more, since it is now an adult ISA. |
The estimate in our Junior ISA calculator uses assumed rates, not forecasts, to show what an account could be worth by 18. Investments can go down as well as up, so any stocks and shares Junior ISA may be worth less than was paid in.
What if the child cannot manage their own money at 18?
Gov.uk says that if a young person lacks the mental capacity to manage their affairs at 18, in England and Wales parents or relatives must apply to the Court of Protection for a financial deputyship order. For Scotland it names the Office of the Public Guardian in Scotland, and for Northern Ireland the Office of Care and Protection. The gov.uk manage-an-account page has the details.
Questions to ask the provider before the child turns 18
Each of these depends on the provider, so the answers can differ:
- What type of adult ISA will the Junior ISA become, and will the interest rate or investments stay the same?
- Will the provider write to the child, to the parent, or to both, and how far in advance?
- What identity checks will the child need to pass, and what documents are needed?
- Are there any charges or changes to fees once the account becomes an adult ISA?
- If the child wants to move the account to another provider afterwards, how does the provider handle an ISA transfer, and how long does it take?
- What happens to any regular payments set up by the parent or another person, such as a standing order?
- If the account holds investments, are they sold or kept when the account converts?
- Can the child see the account online from 16, and what does the provider need to set that up?
For a summary of gov.uk's guidance on managing the account, see its manage a Junior ISA page.
Frequently asked questions
Can a child withdraw from a Junior ISA at 16?
No. At 16 the child can take over management as the registered contact, but gov.uk says money cannot be taken out until they turn 18, apart from the terminal illness and death cases described on gov.uk.
Does a Junior ISA turn into an adult ISA on its own?
Yes. Gov.uk states that Junior ISAs automatically turn into adult ISAs when the child turns 18. The pages read for this guide do not say what type of adult ISA it becomes or how the provider communicates the change, so ask the provider.
Can a child aged 16 or over open an ISA?
Gov.uk says you must be 18 or over to open an ISA, and that a child aged 16 or over can open their own Junior ISA. The pages read for this guide say nothing about an adult Cash ISA for a younger person; ask a provider that offers one to explain the product and its terms.
Does the Junior ISA use up the adult ISA allowance?
gov.uk gives the Junior ISA yearly limit (£9,000) and the adult allowance (£20,000) as separate figures. The pages read for this guide do not say whether payments into a child's account affect an adult's allowance, so HMRC or the provider can confirm the position for a particular family.
Who can pay into a Junior ISA?
Gov.uk says anyone can pay money into a Junior ISA, but the total paid in cannot go over the yearly limit of £9,000, which covers all of the child's Junior ISAs. Only the registered contact can manage the account.
This guide does not constitute financial advice. Your personal situation, tax position, and savings goals may mean different strategies are appropriate. Consider speaking to a regulated financial adviser if you are uncertain.
