How much can I put in a Junior ISA?

You can pay up to £9,000 into a Junior ISA for each child in every tax year. That is the whole allowance: it covers everything paid in by parents, grandparents and anyone else, and it is set per child rather than per person contributing¹.

The limit is not a target and it is not a lifetime cap. It resets on 6 April each year, and anything you do not use by 5 April is gone, because unused ISA allowance cannot be carried into the next tax year². Government guidance states that junior ISAs and Child Trust Funds will stay at £9,000 until April 2031, so the figure is not expected to move in the near term³.

A child can hold one Junior Cash ISA and one Junior Stocks and Shares ISA at the same time, and the £9,000 is shared across both rather than applying to each⁵. Money in a Junior ISA cannot be withdrawn until the child turns 18, when the account becomes an adult ISA in their name⁷.

Junior ISA allowance: £9,000 per child each tax year

The £9,000 figure is the annual subscription limit, the maximum that can be paid into a child's Junior ISA in a single tax year. It applies to every child under 18 who is eligible, and it is the same whether the money goes into a cash account, a stocks and shares account, or a mix of the two¹.

The limit is set by government and reviewed periodically rather than fixed permanently. It has risen several times since Junior ISAs were introduced, and each change has been made through legislation. The current £9,000 is confirmed in official guidance and repeated across providers' own documents, which is why the same figure appears whether you read a government page or a bank's product information¹.

Because the allowance is per child, a family with several children can pay £9,000 into each child's account in the same tax year. Three children means three separate £9,000 allowances in one year, all of it sheltered from income tax and capital gains tax. That is the per-child figure applied to each child, not a separate allowance.

The tax year runs from 6 April to 5 April. Payments made on or before 5 April count towards that year's £9,000; payments from 6 April count towards the next year's. There is no facility to backdate a contribution into a previous year, and no way to bring forward a future year's allowance².

Splitting the £9,000 between cash and stocks and shares

A child can hold one Junior Cash ISA and one Junior Stocks and Shares ISA at the same time, and the £9,000 is a single pot shared between them⁵. If you put £3,000 into the cash account, £6,000 is left for the stocks and shares account, and the other way round. You cannot put £9,000 into each.

The two types behave differently, and that difference matters more than the split itself. A Junior Cash ISA holds money in a savings account, so the value does not fall, but inflation can erode what it buys over a long period. A Junior Stocks and Shares ISA holds investments, so the value can fall as well as rise, and the money is usually better suited to a longer timescale¹¹.

Because the allowance is shared, moving money between the two accounts within the same tax year does not create extra allowance. A transfer from one Junior ISA to another provider also does not use up allowance, and the one-of-each-type rule continues to apply after a transfer¹⁰.

Who can pay into a child's Junior ISA

Anyone can pay into a child's Junior ISA, including parents, grandparents and other relatives⁹. The money does not come out of the adult's own ISA allowance, because the account belongs to the child, not to the person contributing⁵. A grandparent can therefore use their own £20,000 adult allowance in full and still pay into a grandchild's Junior ISA.

The account itself is opened by a parent or legal guardian for a child under 18¹⁵. Once it is open, other people can pay in. Some providers give the account holder a reference so that family members can make contributions directly, and others accept payments from a linked account.

The £9,000 limit applies to the child, not to each contributor. If a parent pays in £5,000 and a grandparent pays in £5,000, the total of £10,000 breaches the limit even though neither person individually exceeded it. That is why providers ask for the child's details and track contributions across the account rather than per payer¹⁶.

Minimum deposits: from £1 to £100 lump sums

There is no minimum set by the rules. The £9,000 is a ceiling, and providers set their own minimums, which vary widely. At one end, NS&I accepts investments from £1 up to £9,000 in the tax year 2026/27¹³. Several building societies also take £1 minimum deposits on their Junior Cash ISAs, including Coventry, Beverley, Bath, Loughborough and Nottingham Building Societies¹⁷.

At the other end, many investment providers set a higher entry point. Hargreaves Lansdown allows a Junior Stocks and Shares ISA to be opened or topped up from a £100 lump sum or £25 a month⁶. Fidelity sets a regular savings plan from £25 or a lump sum from £100¹⁸. NatWest allows a lump sum of £50 or more, or monthly deposits from £10¹⁵. Coventry Building Society's Junior Cash ISA accepts between £1 and £9,000¹⁹.

The practical effect is that a child can start with very little, and the choice of provider often matters more than the amount for the first few years. A £1 minimum cash account and a £100 minimum investment account are both within the same £9,000 annual limit, so the limit itself does not change with the provider.

The limit is per child, not per person paying in

The single most common misunderstanding about the Junior ISA allowance is that it belongs to the person paying in. It does not. Each child has their own £9,000 allowance for the tax year, and it is unaffected by how many adults contribute or how much those adults save elsewhere⁵.

That has two consequences. First, a family with several children can shelter £9,000 for each of them in the same year, which is a much larger figure than any one adult's ISA allowance. Second, a child's allowance cannot be pooled: you cannot move one child's unused allowance to a sibling, and you cannot use a child's allowance to shelter money that belongs to an adult.

The allowance also does not depend on who opened the account. A parent or legal guardian opens it, but the money in it belongs to the child, and the child takes control of the account at 18⁷. Until then, the money is locked in, and withdrawals are not permitted except in the limited circumstances the rules allow⁸.

What happens if more than £9,000 is paid in during one tax year

Paying in more than £9,000 in a tax year means part of the money is not a valid ISA subscription. Providers are expected to monitor contributions and stop accepting money once the limit is reached, so in practice an overpayment should be refused or returned rather than accepted and left in place¹⁶.

If an invalid subscription does happen, the excess is not entitled to the tax-free treatment that applies inside an ISA. The rules on invalid subscriptions allow the position to be corrected, usually by returning the excess to the contributor, and the tax-free status of the rest of the account is not affected. The detail sits in the ISA regulations rather than in provider terms¹⁰.

There is no penalty charge for an accidental overpayment in the way there is for some other tax wrappers. The risk is administrative: money sitting outside the wrapper, tax to sort out, and a correction process that takes time. Checking the running total before the end of the tax year is the simplest way to avoid it.

Does the unused Junior ISA allowance carry over?

No. The allowance resets at the beginning of each tax year, and any part of the £9,000 that is not used by 5 April is lost². There is no carry-forward, no partial carry-forward, and no way to use a previous year's unused allowance in a later year.

This is the same rule that applies to the adult ISA allowance, which also resets every 6 April². It is different from the rules for some other tax allowances, such as the capital gains tax annual exempt amount, which also resets but operates on a different basis. For Junior ISAs, the reset is absolute.

The practical implication is that a lump sum paid in March uses the current year's allowance, while the same payment made in April uses the next year's. If a child has a large amount to invest, spreading it across two tax years can use two allowances, but each year's £9,000 is separate and neither can be borrowed from the other.

Will the April 2027 ISA changes affect the Junior ISA limit?

No. The changes announced for 6 April 2027 affect the adult cash ISA limit, not the Junior ISA limit. From that date, the annual cash ISA subscription limit is set at £12,000 for investors under the age of 65, while for investors aged 65 and over it remains at £20,000³.

The Junior ISA limit is a separate figure and is not part of that change. Government guidance states that junior ISAs and Child Trust Funds will remain unchanged at £9,000 until April 2031³. The consultation on the 2026 regulations confirms the cash ISA change applies to investors below the age of 65 from 6 April 2027, and does not alter the junior limit²³.

For a child, the practical position is therefore unchanged: £9,000 a year, shared across one cash and one stocks and shares Junior ISA, until at least April 2031. The adult changes matter to the person paying in only in relation to their own ISA, not the child's.

What was the Junior ISA allowance before it rose to £9,000?

The limit has been increased several times since Junior ISAs were introduced. It was set at £3,600 when the accounts launched, following a consultation that raised the proposed figure from £3,000²⁵. It then rose to £3,720, and to £3,840 from 2014²⁶.

For the 2014-15 tax year the limit was increased to £4,000²⁷. It later reached £4,128, and from 6 April 2018 it rose from £4,128 to £4,260²⁸. Further increases have since taken it to the current £9,000, which is confirmed in official statistics and in the Autumn Budget 2024 rates and allowances⁸.

Each change was made by statutory instrument rather than announced as a permanent figure, which is why the limit has moved in steps rather than in one jump. The pattern is a periodic review rather than an annual uprating, and the current guidance confirms no change before April 2031³.

Matured Child Trust Funds and unclaimed savings

A child cannot have a Child Trust Fund and a Junior ISA at the same time³⁰. To move from one to the other, the whole Child Trust Fund has to be transferred into the Junior ISA, which preserves the tax-free status. Partial transfers are not allowed, and the one-of-each-type rule for Junior ISAs continues to apply afterwards³⁰.

Child Trust Funds were issued to children born between 2002 and 2011, and many have now matured. HMRC data shows over 827,000 matured Child Trust Funds worth £2,310 on average were still unclaimed³². A matured account belongs to the young person, who can access it at 18, and it can be transferred into a Junior ISA or an adult ISA at that point.

There is also a separate provision for children who have been in local authority care. Children who have been in care for 12 months or more and who are not eligible for a Child Trust Fund are entitled to a £200 one-off government payment into a Junior ISA³³. That payment counts towards the £9,000 annual limit in the year it is made.