Junior ISA projector
See what a Junior ISA could be worth on the child’s 18th birthday. Set a monthly amount and a growth rate, and compare a cautious cash return against stocks.
That is over the £9,000 a year limit, so the monthly amount has been capped at £750.
How the projection works
The tool grows your starting balance and each monthly payment at the rate you choose, compounding month by month until the child turns 18. It holds the £9,000 a year limit, so if a monthly figure would break that it is capped at £750. The result is the pot the child inherits on their 18th birthday, when the account becomes theirs and switches to an adult ISA.
The cash and stocks figures beside the main number use fixed assumptions of 3% and 6% a year so you can see the spread. Real returns are never this smooth. Cash is steadier but tends to trail inflation, while a stocks and shares JISA can grow more over a long stretch and can also fall, so the gap shown is a guide to the trade-off rather than a forecast.
Worked example
Start at age 3 with nothing saved and pay in £100 a month at 5% a year. Over 15 years you contribute £18,000, and steady growth lifts the pot to about £26,482 by age 18, so roughly £8,482 is growth. At a cautious 3% the same payments reach about £22,624, and at 6% about £28,691, which shows how much a few percentage points matter across a childhood.
Common questions
How much can I pay into a Junior ISA?
The Junior ISA limit is £9,000 a tax year, which is £750 a month. That allowance covers a cash JISA and a stocks and shares JISA together, so paying into both still shares the same £9,000.
When can the money be taken out?
The child cannot access the money until they turn 18, and neither can you once it is paid in. At 18 the account becomes theirs and an adult ISA, and they decide what happens to it. That lock is the point of the account, but it is worth being sure before you commit.
Cash or stocks and shares Junior ISA?
Over a long run to age 18, a stocks and shares JISA has usually grown faster than cash, but it can fall in value and is not guaranteed. Cash is steadier but often loses ground to inflation. The comparison here shows the gap a few percentage points of growth make over many years.
Who can pay into a Junior ISA?
A parent or guardian opens it, but anyone can contribute, so grandparents and family can add money too. Everything paid in still counts towards the single £9,000 yearly limit for that child.
Does a Junior ISA affect my own ISA allowance?
No. The £9,000 Junior ISA limit is separate from your own £20,000 adult ISA allowance, so paying into a child’s JISA does not reduce what you can save yourself.