Why starting early matters more than how much you save
The single biggest driver of how much your child ends up with isn't how much you save each month — it's how early you start. This is because of compounding: your returns generate their own returns, and over 18–21 years the effect becomes dramatic.
Waiting five years to start costs nearly £18,000 in final outcome — on the same monthly contribution. This is why the best time to start saving for a child is always as soon as possible, ideally from birth.
Your options at a glance
| Option | Tax on growth | Annual limit | Access before 18 | Verdict |
|---|---|---|---|---|
| Junior Stocks & Shares ISA | None | £9,000 | No (by design) | Best for growth |
| Junior Cash ISA | None | £9,000 combined | No | Safe, lower return |
| Children's savings account | Possible (above allowance) | None | Yes | Flexible, lower rate |
| Premium bonds | None (prizes tax-free) | £50,000 | Yes (via parent) | Safe, variable return |
| Bare trust / investment account | CGT & income tax apply | None | Yes | Flexible, tax-exposed |
| Pension (JIPP/SIPP for child) | None (inside pension) | £3,600 gross | No (until ~57) | Very long-term |
Option 1: Junior Stocks & Shares ISA — the best choice for most families
A Junior Stocks & Shares ISA is the most powerful long-term savings vehicle available for children in the UK. Any investment growth and income earned inside the ISA is completely free from income tax and capital gains tax — forever. The account belongs to the child but can't be accessed until they turn 18.
The annual allowance is £9,000 — far more than most families contribute — which means there's room for grandparents, godparents, and other family members to contribute alongside parents without hitting the limit.
Over 18 years, investing £9,000 per year (the full allowance) at 8% per year would produce a fund worth approximately £380,000 by age 18. Even at modest contributions, the tax-free compounding effect over that period is significant.
Only a parent or legal guardian can open a Junior ISA — but once open, anyone can pay in. You can have one Junior Cash ISA and one Junior Stocks & Shares ISA at the same time, but the £9,000 limit applies across both combined. The account converts to an adult ISA at age 18.
Option 2: Junior Cash ISA — safe but limited
A Junior Cash ISA offers the same tax-free wrapper as the Stocks & Shares version, but holds cash rather than investments. The upside is that the value can't fall. The downside is that over 18 years, cash interest rates have historically fallen well short of stock market returns.
For shorter time horizons, or for parents who want a portion of their child's savings in a guaranteed-return product, a Junior Cash ISA is a reasonable choice. For the full 18-year horizon, though, a Stocks & Shares ISA has historically produced significantly higher returns.
You can hold both types simultaneously — the £9,000 limit applies to the combined total.
Option 3: Children's savings accounts
High street children's savings accounts from banks and building societies are easy to open and offer immediate access. The best rates in 2025 are around 4–5% AER, which is competitive for cash.
The tax position is worth understanding: children have their own personal allowance (£12,570) and starting rate for savings (£5,000 at 0%), which means most children will pay no tax on interest regardless. However, if the money comes from a parent and generates more than £100 in interest per year, it's taxed as the parent's income — a rule designed to prevent parents sheltering money in children's accounts.
For most families, a children's savings account is a good place to hold an emergency fund or shorter-term savings, while a Junior ISA handles the long-term wealth building.
Option 4: Premium bonds
Premium bonds can be held in a child's name (managed by the parent or guardian until age 16). All prizes are tax-free, and the prize fund rate in 2025 is 4.4% — but this is the average. In practice, most bondholders receive less than this in any given year, and some receive nothing. The return is variable and luck-dependent.
Premium bonds are capital-secure — your money doesn't fall in value — and can be cashed in at any time. They're a reasonable option for grandparents wanting to make a gift with some element of excitement, but not the best vehicle for systematic long-term wealth building.
Option 5: Investing on behalf of a child — bare trusts
Some investment platforms allow you to open an account designated for a child outside of the ISA wrapper. These are sometimes called bare trusts or designated accounts. There's no annual contribution limit, which makes them useful when you've used up the £9,000 JISA allowance and want to invest more.
The downside is tax exposure. Capital gains and income above the child's allowances are taxable — and as above, the £100 parental income rule applies to money gifted by parents. These accounts are more complex and generally only worth considering once the ISA allowance is fully used.
What about a pension for a child?
Yes — you can open a pension for a child. A parent or guardian can contribute up to £2,880 net per year (£3,600 gross with basic rate tax relief) into a Junior SIPP. The money grows completely free of tax, and the compounding over 50+ years is extraordinary.
The obvious limitation is that your child won't be able to access it until their late 50s. For families who want to give their child a genuine financial head start at 18 or 21, a Junior ISA is more relevant. A child's pension is an excellent supplementary option for grandparents wanting to set up something for the very long term.
The family gifting question
One of the most underused aspects of saving for children is the family network. Grandparents, godparents, aunts and uncles all tend to want to do something meaningful for children in their lives — but most end up defaulting to cash gifts that get absorbed into day-to-day spending.
If those same contributions went into a Junior ISA instead, the difference at age 18 would be significant. Even irregular contributions — birthday gifts of £50, Christmas gifts of £100 — compound meaningfully over 18 years inside a tax-free wrapper.
If parents invest £50/month and grandparents add £50/month from birth to age 21, the projected fund at 8% p.a. grows to around £95,000 — double the solo contribution. Involving the family isn't just nice to have — it materially changes the outcome.