Stable Numbers
Junior ISA Calculator
Model a Junior ISA with monthly or yearly contributions, the £9,000 annual cap, growth, fees and inflation. See the projected pot at age 18, totals paid in and real-terms value. Share your setup and export a schedule.
Contributions are allowed until the child turns 18.
Used for neat month labels in the schedule.
The yearly cap applies to the sum of all contributors.
Assumed paid at the start of each funded year.
Default £9,000. Editable in case the rules change.
Growth, fees and inflation
Important: Junior ISA money belongs to the child. Grown ups cannot withdraw it. Access usually starts at age 18 when the account becomes an adult ISA in the child’s name.
Show yearly schedule
| Year | Your contributions | Fees | Growth | End value | Real value |
|---|---|---|---|---|---|
Annual view. Internally the model compounds monthly for growth and fees and caps each tax year to your allowance.
About this calculator
A Junior ISA lets family and friends contribute tax efficiently for a child’s future. The annual subscription limit is applied across all contributors together. This tool caps each tax year’s contributions to your allowance, then applies growth and fees on a monthly basis to reflect real compounding. If you set a start date the schedule will display tidy labels.
The pot is locked for the child’s benefit. Adults cannot withdraw the funds. At age 18 the Junior ISA usually converts to an adult ISA in the child’s name and they gain full control. Treat growth rates as planning assumptions only. Fees are near certain, so keep an eye on them.
Explore more in the finance tools hub.