Freedom Isn’t Free UK Personal Finance
Investing
Junior ISA UK: The Complete 2026/27 Guide
Most British parents open the wrong type of Junior ISA out of habit. By the child's 18th birthday, the default has quietly cost them the price of a small car. The fix is one form.
JISA value at age 18 (£100/month for 18 years)
Cash JISA at 4%~£31,000
Stocks & Shares JISA at 7%~£43,000
£12,000 gap for the same monthly contribution. Time is the JISA's superpower.
Key takeaways
1
The 2026/27 Junior ISA allowance is £9,000 per child, paid in by anyone, growing tax-free
2
A Stocks and Shares JISA almost always beats a Cash JISA over an 18-year horizon
3
The money legally belongs to the child and they get full control at 18
4
£100 per month from birth at 7% growth becomes roughly £43,000 by age 18