What happens if you don’t use a children’s ISA allowance? A long-term view
A Children’s ISA allowance resets each year, and the allowance for 26/27 remains unchanged from 25/26. The allowance currently stands at £9,000 per year and can be used fully, partially or, of course, not at all. This piece explains what this means in practice over time.
How the children’s ISA allowance works
There are currently no published plans to increase the Junior ISA allowance for 27/28 but this should become apparent from the next budget. The Junior ISA allowance applies per child and not per ISA. Why? Because there are two kinds of Junior ISA, a cash Junior ISA, which is more akin to a savings account, and an Investment Junior ISA, which is what we specialise in here at the Children’s ISA. The Junior ISA allowance cannot be carried over to the next tax year so is very much a use it or lose it.
What happens if you don’t use the allowance
As above, unused Junior ISA allowances expire at the end of the tax year. Regardless of what is invested and if the allowance is used or not, the account remains open and future tax years remain unaffected. Here at the Children’s ISA, we find that different families use the allowance in different ways over time. This always tends to result in a spike in contributions (and new account openings) towards the end of the tax year.
How different approaches to a children’s ISA allowance play out over time
| Approach | What it looks like in practice | How families typically use it | What to understand about the allowance |
| Full allowance used each year | Contributions spread monthly or added in lump sums | Contributions are spread monthly or added in lump sums | The full annual allowance is used, and resets the following tax year |
| Partial contributions | Smaller, irregular amounts depending on affordability | Common among parents balancing childcare, mortgages and other costs | Any unused portion of the allowance cannot be carried forward |
| Occasional contributions | Ad hoc payments, often around birthdays or milestones | Popular with grandparents or extended family | The allowance is flexible, but still limited to each tax year |
| No contributions in a given year | Account remains open but unfunded | Happens during financially tighter periods or uncertainty | The allowance for that year expires and does not roll over |
| Starting later | Contributions begin when a child is older | Families who delay due to competing priorities | The same annual allowance applies, regardless of when contributions begin |
Why doesn’t every family use the full allowance?
Of course, not every family will be in a position to make the full contribution to their child’s ISA each year. Each family’s set of circumstances is unique, and each will have different financial priorities. Contributing factors can be that income becomes irregular or circumstances change. Another factor could be geopolitical; people tend to become nervous about long-term commitments if the global scene appears more unstable.
How families typically contribute in practice
When we look at the pattern of behaviour across our accounts, we generally see these patterns forming. Regular contributions from parents/guardians, coupled with more sporadic contributions from friends and family members (like grandparents). Importantly, there are no set rules for contributions, but over time and with compounding interest, accounts that see regular contributions will tend to perform better than those where payments are more ad hoc.
Who contributes to a children’s ISA and how it usually works
| Contributor | Typical motivation | How contributions are made | Key point to know |
| Parents | Long-term financial planning | Monthly direct debit or ad hoc payments | Contributions count towards the same annual allowance |
| Grandparents | Gifting and legacy | Lump sums for birthdays, Christmas or milestones | Anyone can contribute, but the total is capped each year |
| Other family members | Occasional gifts | One-off payments | Contributions are simple but still fall within the annual limit |
The role of time in a children’s ISA
Because, in theory, a Junior ISA could be paid into from birth, compounding gains could be seen until a child turns 18, and even beyond. A Junior investment ISA could be viewed through the lens of a pension. Like all investments, funds can go up as well as down, over the long term and in our experience, investments will always outpace cash. When the child does reach adulthood, the Junior ISA simply converts into an adult one.
Opening and managing a children’s ISA
Opening a children’s ISA is straightforward and designed to be managed with minimal administration over time.
Who can open it
A parent or legal guardian must open the account. Once set up, the account is held in the child’s name and remains in place until they turn 18.
How contributions work
Contributions can be made by parents, grandparents, family members or friends. All payments go into the same account and count towards the annual allowance for that child.
Flexibility of payments
There is no requirement to contribute a fixed amount or on a set schedule. Payments can be made regularly, occasionally, or paused altogether, depending on what suits the family at any given time.
Key points to remember
- The allowance resets each tax year
- Unused allowance cannot be carried forward
- Contributions can be made in a way that suits different circumstances
- Anyone can contribute, provided the total stays within the annual limit
Understanding how the allowance works over time helps families decide how and when to use it.
