ISA vs JISA — Calculator
Educational only — not financial advice.
Inputs
Years to 18: 15
Up to ~£750 / month (annual cap £9,000).
Up to ~£1666 / month (annual cap £20,000).
Starting balances (optional)
Results (to age 18)
JISA
£26,729
Monthly: £100
Adult ISA
£53,458
Monthly: £200
Period: 15 year(s) to age 18.
Growth: 5% nominal, monthly compounding.
JISA funds locked until 18; Adult ISA flexible.
What this shows (simple)
- Both wrappers grow Tax-free inside the ISA/JISA.
- JISA cap smaller but funds ring-fenced until 18.
- Adult ISA higher cap and access, but needs discipline.
Educational only — not financial advice.