Junior ISAs Explained: Invest for Your Child Tax-Free

Here is the Junior ISA explained in plain terms: it is a long-term, tax-free savings and investment account for a child, locked until they turn 18, that lets you and anyone else build a pot they cannot touch until adulthood. For a parent thinking in decades rather than months, it is one of the most efficient wrappers available, because everything inside it grows free of UK income tax and capital gains tax, and the money genuinely compounds over a long enough runway to matter. This guide covers the rules that actually affect your decisions: the allowance, the two types, who controls the money, and the one feature that trips people up when the child turns 18.

What a Junior ISA is

A Junior ISA (JISA) is a tax-free account for anyone under 18 who lives in the UK. It replaced the Child Trust Fund, and it comes in two forms that sit under a single allowance:

• A Junior Cash ISA, which works like a children’s savings account but with tax-free interest.
• A Junior Stocks and Shares ISA, which holds investments such as funds, shares and bonds, aiming for higher long-term growth in exchange for short-term ups and downs.

A child can hold one of each at any time, and you can split the annual allowance between them however you like. All returns, interest, dividends and growth, are free of tax, and the child never has to declare them.

The £9,000 allowance

For the 2026/27 tax year, you can pay up to £9,000 into a child’s Junior ISA. A few things worth knowing about that figure:

• It is per child, per tax year, not per account. If a child has both a cash and a stocks and shares JISA, £9,000 is the combined ceiling.
• It is completely separate from your own £20,000 adult ISA allowance. Funding a child’s JISA does not reduce what you can shelter yourself.
• It does not carry over. Whatever you do not use by 5 April is lost; you cannot double up next year.

You do not have to use anywhere near the full amount. Regular monthly contributions, even small ones, are how most families use a JISA, and they smooth out the ups and downs of investing over time.

Who can open one and who can pay in

This is the part people most often get wrong, so it is worth being precise:

• Only a parent or legal guardian can open a Junior ISA and act as the “registered contact” who manages it.
• Anyone can pay in. Grandparents, godparents, friends and family can all contribute, as long as the combined total across the year stays within the £9,000 limit. This makes a JISA a tidy home for birthday and Christmas money that would otherwise be spent.

Once open, the registered contact chooses the investments and can switch providers, but the money legally belongs to the child.

Cash or stocks and shares?

For a newborn or young child, the time horizon is the deciding factor. With ten or fifteen years before the money is touched, a stocks and shares JISA has historically given a real chance of outpacing both cash and inflation, and the long lock-in is exactly the condition under which investing works best. Short-term volatility matters far less when you are not selling for over a decade.

A cash JISA makes more sense when the child is already a teenager and the pot will be needed soon, or if you simply cannot tolerate seeing the value fall. Many parents use a stocks and shares JISA through the early years and consider moving toward cash as 18 approaches. You can transfer between the two, and between providers, without losing the tax-free status, so you are not locked into your first choice. See our guide on how to transfer an ISA for the mechanics.

Keep an eye on charges. On a stocks and shares JISA, a low-cost global index fund inside a low-fee platform keeps more of the growth in the child’s pocket over 18 years, which is the whole point of starting early.

What happens at 18

At 18, the Junior ISA automatically becomes a normal adult ISA, and the money becomes entirely the young adult’s to do with as they wish. Two practical points flow from that:

• The child can take control of the account at 16, becoming the registered contact, though they still cannot withdraw any money until 18.
• Once they turn 18, you have no say over how the money is used. For most families this is fine; for some it is worth thinking about before you fund a large pot, and it is a good reason to talk to your child about money as they grow up.

Because the account rolls straight into an adult ISA, the tax-free wrapper continues seamlessly if they leave it invested, which can be the start of a lifelong investing habit.

Is a Junior ISA worth it?

For most families saving for a child’s future, yes. The tax shelter, the long time horizon and the ability for relatives to contribute make it hard to beat for a genuinely long-term goal. The two honest caveats are that the money is locked until 18 and out of your control after that. If you might need access before then, a JISA is the wrong tool. For the official rules, the government’s Junior ISA guidance and MoneyHelper’s Junior ISA pages are the authoritative references. For how ISAs work more broadly, see our guides to the Lifetime ISA and whether you can hold multiple ISAs.

Frequently asked questions

What is the Junior ISA allowance for 2026/27? You can pay up to £9,000 into a child’s Junior ISA in the 2026/27 tax year. This is per child, covers both a cash and a stocks and shares JISA combined, and is separate from your own £20,000 adult ISA allowance. Unused allowance cannot be carried forward.

Who can open a Junior ISA? Only a parent or legal guardian can open a Junior ISA and act as the registered contact who manages it. However, once it is open, anyone, including grandparents and family friends, can pay in, as long as the yearly total stays within the £9,000 limit.

Can I withdraw money from a Junior ISA? No. Money in a Junior ISA is locked until the child turns 18, with no early withdrawals in normal circumstances. The child can take over managing the account at 16, but cannot access the funds until their 18th birthday, when it becomes an adult ISA.

Should I choose a cash or stocks and shares Junior ISA? For a young child with over a decade until 18, a stocks and shares JISA has historically offered better long-term growth and the time to ride out volatility. A cash JISA suits teenagers close to 18 or parents who cannot accept the value falling. You can transfer between them tax-free.

Does a Junior ISA affect my own ISA allowance? No. The £9,000 Junior ISA limit is entirely separate from and in addition to your personal £20,000 adult ISA allowance. Paying into your child’s JISA does not reduce how much you can shelter in your own ISAs.

What happens to a Junior ISA when the child turns 18? At 18 the Junior ISA automatically converts into a standard adult ISA and the money becomes the young adult’s to control. They can withdraw it, keep it invested tax-free, or transfer it, and the parent no longer has any say over how it is used.