A Junior ISA — or JISA — is a tax-free savings or investment account for children under 18. It works like an adult ISA in most respects: interest and returns inside the wrapper aren't taxed, and contributions count towards an annual allowance. The key differences are the lower allowance (£9,000 per year for 2025/26), the lock-in until the child turns 18, and the fact that the child owns the money — once they turn 18, it's theirs.
This guide explains how Junior ISAs work, who can open and contribute to one, and the calculator above shows how the pot grows over time.
Who Can Open a Junior ISA
A Junior ISA can be opened by a parent or guardian with parental responsibility for the child. Once open, anyone can contribute — grandparents, other family members, friends — up to the annual allowance across all contributions combined.
Children born between 1 September 2002 and 2 January 2011 were eligible for the Child Trust Fund scheme instead of a Junior ISA. CTF holders can transfer into a Junior ISA — the transfer is free and doesn't affect the annual allowance in the year of transfer.
Children aged 16 and 17 can open their own Junior ISA. They can also open a standard adult Cash ISA at 16, meaning they can hold both types simultaneously in those two years — the only period where this is possible.
The Annual Allowance
The Junior ISA allowance for 2025/26 is £9,000 per child. This is the total across all Junior ISAs in the child's name — Cash and Stocks & Shares combined.
Unlike adult ISAs, unused Junior ISA allowance cannot be carried forward to the next tax year. Any unused allowance for the year is simply lost.
The allowance resets on 6 April each year, in line with the adult ISA allowance.
Cash JISA vs Stocks and Shares JISA
The same broad distinction applies as with adult ISAs.
Cash JISA: Works like a savings account, earns interest, value cannot go down. Suitable if the child is close to 18 and you don't want the value to fluctuate near the point of access. Also suitable for smaller amounts where investment fees would eat into returns.
Stocks and Shares JISA: Invested in funds or shares. Higher potential return over long periods, but value can go down as well as up. The longer the time until the child turns 18, the more suitable this type becomes — there's more time to recover from any short-term falls and benefit from compounding growth.
Many families use a combination: a Stocks and Shares JISA for the main long-term saving, switching to or adding a Cash JISA as the child approaches 18 to lock in gains.
What Happens at 18
When the child turns 18, the Junior ISA automatically converts to an adult ISA in their name. The tax-free status continues. The young adult can then manage it themselves — withdraw it, leave it, or transfer it to a different provider.
There's no requirement to withdraw, and many 18-year-olds choose to leave the money invested while they decide what to use it for. The ISA wrapper continues to protect it from tax regardless.
It's worth having a conversation with your child about the account before they turn 18 — particularly if it's a Stocks and Shares JISA with a significant balance. Understanding what it is, what it's worth, and what the options are helps them make an informed decision rather than simply withdrawing the whole amount on their 18th birthday.
Grandparents and Other Contributions
Friends and family can contribute to a child's Junior ISA, but cannot open one or manage it themselves. The simplest approach is for them to transfer money to the parent or guardian who manages the JISA, who then deposits it. Some providers allow third-party contributions directly — it's worth checking with your specific provider.
The £9,000 annual allowance applies to all contributions combined, regardless of who makes them. If grandparents and parents are both contributing, it's worth tracking the total to avoid accidentally exceeding the allowance.
Junior ISA vs Other Options
A Junior ISA isn't the only way to save for a child's future. Some alternatives worth knowing about:
Premium Bonds for children: Available as a gift from parents, guardians, or grandparents. Accessible at any time (not locked until 18), government-backed, tax-free prizes. More flexible than a JISA but without the tax wrapper protecting compound growth. See our Premium Bonds guide for details.
Regular saver for the child: Some banks offer regular savers in a child's name or in trust. Higher short-term interest rates, but the high rates are temporary (usually 12 months).
Adult ISA when they turn 18: Starting their adult ISA the moment they turn 18 is a valuable habit — they get their first year of allowance early and benefit from compound growth over their working years.
Remember: the money in a Junior ISA legally belongs to the child. Once they turn 18, you have no control over what they do with it. If you want to retain control over money saved for a child, a savings account in your own name earmarked for the child may be more suitable.
Frequently Asked Questions
Yes — one of each is allowed simultaneously. Contributions across both count towards the single £9,000 annual allowance.
Yes. CTF holders can transfer to a JISA at any time. The transfer doesn't count as a new subscription and doesn't affect the annual allowance. Many providers handle the transfer process directly.
The money is locked until 18 in almost all circumstances. The only exception is terminal illness — there is a process to access funds early in this situation. For savings you might need access to before 18, a different savings vehicle is more appropriate.
Children aged 16 and 17 can manage their Junior ISA — they can give instructions to the provider, though they still cannot withdraw until 18. Under 16, the account is managed solely by the registered contact (parent or guardian).
Yes — Junior ISAs held with UK-authorised banks and building societies are protected under the FSCS up to £85,000. For Stocks and Shares JISAs, the FSCS protects up to £85,000 against provider insolvency, though not against investment losses.
This guide provides general information about Junior ISAs and is not financial advice. Allowances and rules are subject to change. Stocks and Shares JISA values can go down as well as up. For guidance on investment decisions, speak to a financial adviser.