Many parents and grandparents want to give a child a financial head start, and a Junior ISA (JISA) is the tax wrapper the UK government designed for exactly that. Money invested inside a JISA can grow free of Capital Gains Tax and further dividend tax, in the same way as an adult Stocks & Shares ISA, but with rules of its own around access, ownership, and what happens at 18.
How a Junior ISA works
A Junior ISA can be opened by a parent or legal guardian for a child under 18 who is resident in the UK. Once opened, anyone can contribute to it — parents, grandparents, other family members — up to the annual JISA allowance, which is £9,000 for the 2025/26 tax year. This is a separate allowance from the adult £20,000 ISA allowance, so a parent can fund their own ISA and a child's JISA in the same tax year without either affecting the other.
As with adult ISAs, there are two main types: a Cash JISA and a Stocks & Shares JISA. A child (or their parents, on their behalf) can hold one of each type, or split contributions between them, but the combined total across both must stay within the £9,000 annual allowance.
Who owns the money
This is one of the most important things for parents to understand: the money in a JISA legally belongs to the child from the moment it's paid in. Parents or guardians act as the account's "registered contact" and manage it on the child's behalf, but they cannot withdraw the money for their own use, and the funds cannot be accessed by the child until they turn 18. This is different from, say, a bare trust or a regular savings account held informally in a parent's name.
Why use a Stocks & Shares JISA rather than Cash
Because a JISA typically has a long time horizon — potentially close to 18 years, if opened at birth — many parents consider the same reasoning that applies to long-term adult investing: cash savings can be eroded by inflation over long periods, whereas stock market investments have historically had a greater chance of real (inflation-adjusted) growth over long timeframes, albeit with more volatility along the way and no guarantee of any particular outcome.
A Stocks & Shares JISA can typically hold the same broad range of investments as an adult ISA: index tracker funds, actively managed funds, investment trusts, and individual shares, depending on the provider. Many parents choose diversified, low-cost global funds for a JISA given the multi-year runway before the child can access the money, though the right choice depends on individual circumstances and risk tolerance.
Cash JISA versus Stocks & Shares JISA
A Cash JISA works much like an ordinary savings account, paying interest tax-free, with no risk to the capital deposited (subject to the usual Financial Services Compensation Scheme protections). A Stocks & Shares JISA instead invests the money in the markets, meaning the value can fall as well as rise over time, but with the potential for greater long-term real growth given the typically long timeframe involved. Some families split contributions between both types — for example, keeping a smaller cash buffer for near-term flexibility around the child's 18th birthday while investing the bulk of contributions for growth over the earlier years.
Switching between JISA types
A JISA held in cash can generally be transferred into a Stocks & Shares JISA (or vice versa) without losing its tax-free status, provided the transfer is done directly between providers rather than by withdrawing and reopening. This means a family is not locked into their original choice of JISA type for the full 18 years, and can adjust the balance between cash and investments as the child's access date approaches.
Contributing to a JISA
Who can pay in
Contributions are not restricted to parents. Grandparents, other relatives, and friends can all contribute directly to a child's JISA, which makes it a popular vehicle for birthday and Christmas gifts that might otherwise go straight into low-interest savings or be spent. Many providers allow one-off or regular contributions from anyone with the account details.
The £9,000 allowance in practice
Because £9,000 is a substantial sum relative to typical gifting patterns, most JISAs in practice hold well under the maximum allowance each year — but for grandparents or family members looking to pass on wealth in a tax-efficient way over time, using some or all of the JISA allowance annually can be a meaningful part of a wider family financial plan.
What happens when a child turns 16 and 18
| Age | What changes |
|---|---|
| 16 | The child can, in some cases, take over management of the JISA themselves, though the money remains locked until 18. They also become eligible to open an adult Cash ISA (but not a Stocks & Shares ISA) at 16 in current rules, which is separate from the JISA. |
| 18 | The JISA automatically converts into an adult ISA. At this point the funds legally and practically belong entirely to the now-adult child, who has full access and can withdraw or continue investing the money as they choose. |
This automatic conversion at 18 is worth planning for. Some parents find it useful to talk to their child about investing and money management well before this point, since the JISA balance can, for some families, represent a genuinely significant sum handed over to an 18-year-old with no restrictions on how it's used.
A worked example
Suppose a family opens a Stocks & Shares JISA for a newborn and contributes £100 a month, alongside occasional lump sums from grandparents totalling roughly £500 a year — purely as a hypothetical example, this would total around £1,700 a year, well within the £9,000 allowance. Assuming, again hypothetically and not as a forecast, average annual growth of 5% over 18 years, the pot might reach somewhere in the region of £48,000 by the time the child turns 18 — compared with roughly £30,600 in total contributions. The gap illustrates the effect of long-term compounding, though actual outcomes would depend entirely on real market performance over that period, which cannot be known in advance.
For comparison, if the same family instead paid the £1,700 a year into a Cash JISA earning a hypothetical 3% average annual interest rate over the same 18 years, the pot might reach approximately £41,500 — lower than the Stocks & Shares JISA illustration above, reflecting the generally lower long-term return typically associated with cash, though also without the year-to-year fluctuations in value that come with stock market investing. Neither outcome is guaranteed, and actual cash interest rates and market returns both vary considerably over an 18-year period in ways that cannot be predicted from today's figures.
JISA versus a bare trust, at a glance
| Feature | Junior ISA | Bare trust |
|---|---|---|
| Tax on growth and income | Fully tax-free within the wrapper | Taxed as the child's own income/gains, though often covered by the child's own allowances |
| Access age | 18, automatically | Flexible — can be set up to release at a different age or on trustee discretion |
| Annual contribution limit | £9,000 | No formal limit, though large gifts can have other tax implications for the donor |
| Ownership | Child's absolutely, from the point of contribution | Child's absolutely, once the trust is set up in their name |
| Flexibility of investment choice | Limited to the JISA provider's fund range | Can be broader, depending on how the trust is structured |
In practice, many families find the administrative simplicity of a JISA outweighs the additional flexibility a bare trust can offer, particularly since a JISA requires no separate tax reporting.
Things to consider before opening one
Irrevocability
Once money is placed into a JISA, it cannot be taken back out by the parent, and the child cannot access it before 18 except in extremely limited circumstances (such as terminal illness). This makes a JISA a genuinely locked-away, long-term commitment rather than a flexible family savings pot.
Interaction with other tax-efficient options
Some families weigh a JISA against other ways of saving for a child, such as a bare trust, or simply increasing pension or ISA contributions in a parent's own name to be gifted later. A JISA's key advantage is the tax wrapper and the fact that it belongs unambiguously to the child from the outset; its key trade-off is the total loss of parental control once money is paid in.
Only one of each type at a time
A child can only have one Cash JISA and one Stocks & Shares JISA open at any time (transfers between providers are allowed, but not multiple simultaneous accounts of the same type), which is a different rule from adult ISAs, where multiple providers can now be used within a tax year.
Frequently asked questions
Can a JISA be opened for a child born outside the UK?
A JISA generally requires the child to be resident in the UK and not already have a Child Trust Fund (the JISA's predecessor scheme, closed to new accounts). Families in more complex residency situations may need to check eligibility directly with a provider, as the rules can depend on the specific circumstances involved.
What happens to a JISA if the child has an existing Child Trust Fund?
A child cannot hold both a Child Trust Fund and a JISA at the same time, but a Child Trust Fund can be transferred into a JISA, which some families do to access a potentially wider range of investments or lower charges, depending on the provider.
Does a JISA affect a child's other allowances, such as the Personal Allowance?
Since income and gains within a JISA are entirely tax-free and never need to be declared, they have no bearing on a child's Personal Allowance or any other allowance, unlike some other child savings arrangements where income can, in certain circumstances, count towards a parent's tax position.
Key takeaways
- The Junior ISA allowance is £9,000 for the 2025/26 tax year, separate from the adult £20,000 ISA allowance.
- Money in a JISA legally belongs to the child immediately, cannot be withdrawn by parents, and is locked until age 18.
- Anyone — parents, grandparents, family, or friends — can contribute to a child's JISA up to the combined annual allowance.
- A Stocks & Shares JISA can suit long time horizons, though as with any stock market investment there is no guarantee of growth and values can fall as well as rise.
- At 18, a JISA automatically becomes an adult ISA and the now-adult child gains full, unrestricted access to the funds.
- Always check current HMRC figures, as JISA allowances and rules can be revised from one tax year to the next.