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Generational wealth

Junior ISA
growth calculator

£150 a month from birth into a global index fund could give your child roughly £65,000 by their 18th birthday. That's a university fund, a house deposit, or a head start on life.

Tax-free until 18

All growth, dividends, and gains inside a JISA are completely tax-free.

Compound projections

See projected values at 6%, 8%, and 10% annual returns.

Anyone can contribute

Parents, grandparents, aunts, uncles, friends. Up to £9,000/year total.

Age 0-17. The younger they are, the longer compound interest works in their favour.

Regular monthly amount (max ~£750/month to stay within the £9,000 yearly limit)

One-off amount to start with (up to £9,000 annual JISA allowance)

The long-term average stock market return is around 7-10% per year

Free tool. No account required. Your data is not stored.

£150/month at 8% returns

Start at Birth (0)~£65,000

18 years of compound growth

Start at Age 5~£39,000

13 years of compound growth

Start at Age 10~£20,000

8 years of compound growth

Start at Age 15~£6,000

3 years of compound growth

The maths doesn't care about your intentions. It only cares about time.

Common questions

What is a Junior ISA?

A Junior ISA (JISA) is a tax-free savings or investment account for children under 18. You can invest up to £9,000 per year. The child can't access the money until they turn 18, and neither can the parents.

Can I withdraw money from a Junior ISA?

No. The money is locked until the child turns 18. This is a feature, not a bug. It forces long-term thinking and protects the investment from being dipped into.

What happens when my child turns 18?

The JISA automatically converts to an adult ISA. The child then has full control. They can withdraw, keep investing, or transfer to a different provider.

Key facts

  • Annual allowance: £9,000 per child
  • Anyone can contribute (not just parents)
  • Locked until child turns 18
  • Converts to adult ISA automatically
  • Instead of cash gifts that get spent, a JISA grows

Issues with your child's JISA provider?

If your JISA provider has charged unexpected fees, delayed a transfer, or given poor service, we can help you resolve it.

Start your free complaint