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Tools / Savings / Junior ISA Calculator

Find out how much a Junior ISA could be worth by the time your child turns 18. Enter an initial investment, monthly contributions, and an expected annual return rate to see the projected value.

Press Enter to move to the next field. On the last field, Enter moves to the result.

The child’s age is used to calculate the number of years until the child turns 18.
year
The annual contribution limit for a Junior ISA is £9,000, which equates to £750 per month.
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Future value:
£25,816.12

This future value estimate shows what the Junior ISA could be worth by age 18.

* The results provided by this calculator are estimates only and do not constitute financial advice. Actual investment returns can vary due to market conditions, fees, charges, and other factors. View full disclaimer

Summary

When your child is 18, their Junior ISA could be worth£25,816.12

You started with£0.00
Your total contributions over 18 years will be£21,600.00
The estimated growth is£6,553.96
Fees-£2,337.84

This table below shows the breakdown for each year.

YearStarting balanceContributionsInterestFeesEnding balance
0£0.00£0.00£0.00£0.00£0.00
1£0.00£1,200.00£16.64£12.17£1,204.47
2£1,204.47£1,200.00£53.28£24.58£2,433.17
3£2,433.17£1,200.00£90.65£37.24£3,686.58
4£3,686.58£1,200.00£128.77£50.15£4,965.20
5£4,965.20£1,200.00£167.66£63.33£6,269.53
6£6,269.53£1,200.00£207.34£76.77£7,600.10
7£7,600.10£1,200.00£247.81£90.48£8,957.43
8£8,957.43£1,200.00£289.09£104.47£10,342.05
9£10,342.05£1,200.00£331.21£118.73£11,754.53
10£11,754.53£1,200.00£374.16£133.29£13,195.40
11£13,195.40£1,200.00£417.99£148.13£14,665.26
12£14,665.26£1,200.00£462.69£163.28£16,164.67
13£16,164.67£1,200.00£508.30£178.73£17,694.24
14£17,694.24£1,200.00£554.83£194.49£19,254.58
15£19,254.58£1,200.00£602.29£210.57£20,846.30
16£20,846.30£1,200.00£650.70£226.97£22,470.03
17£22,470.03£1,200.00£700.09£243.70£24,126.42
18£24,126.42£1,200.00£750.47£260.77£25,816.12

Frequently Asked Questions

What is a Junior ISA?
A Junior Individual Savings Account (ISA) is a long-term, tax-free savings account for children under 18 in the UK.
How does the calculator estimate future value?
The calculator estimates the future value by considering the initial investment, regular monthly contributions, the expected annual growth rate, and the number of years until the child turns 18 from age of child. It assumes interest is compounded monthly.
How accurate are the results?
This calculator provides estimates based on your inputs and assumed constant interest rates. It is intended for informational purposes only and does not constitute financial advice. Actual investment returns can vary due to market conditions, fees and charges, and other factors. For personalized financial planning, please consult a qualified financial advisor.
What is the annual contribution limit for a Junior ISA?
As of the 2025/2026 tax year, the annual contribution limit is £9,000. This limit may change in future tax years. That works out to £750 a month in the monthly contribution input.
Can I withdraw money from a Junior ISA before the child turns 18?
Generally, funds in a Junior ISA cannot be withdrawn until the child turns 18. There are very limited circumstances where early withdrawal is allowed.
Does the calculator account for inflation?
No, the calculator does not account for inflation. It provides a nominal future value based on the inputs provided.
Are the returns guaranteed?
No, the returns are not guaranteed. The calculator assumes a fixed growth rate for estimation purposes. Actual returns may vary based on the Junior ISA's performance and market conditions.
Have you tried our Compound Interest Calculator?

Calculate how much an investment will grow over time with compounding interest. Enter your principal, interest rate, and compounding frequency to see the future value.

Compound Interest Calculator