UK ISA Calculator 2024-25
Project your ISA growth and tax savings for 2024/25. Covers Stocks & Shares ISA, Cash ISA, and Lifetime ISA (LISA) with government bonus and annual allowance limits.
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How to use this calculator
- 1
Select your ISA type — Stocks & Shares, Cash, or Lifetime ISA (LISA). Each has different annual allowances and uses.
- 2
Enter your planned monthly contribution. The calculator will cap it at the annual allowance limit (£20,000 for most ISAs, £4,000 for LISA).
- 3
Enter your expected annual return as a percentage. Cash ISAs earn interest (currently 4–5%), while Stocks & Shares ISAs historically return around 7–9% per year over the long term.
- 4
The LISA calculator shows the 25% government bonus on contributions, worth up to £1,000 per year.
- 5
All growth within an ISA is completely tax-free — no income tax on interest or dividends, and no capital gains tax on growth.
Frequently asked questions
What is the ISA allowance for 2024/25?
In 2024/25 the annual ISA allowance is £20,000 per person. This is the total you can put across all your ISAs in a single tax year (6 April to 5 April). You can split the allowance between different ISA types — for example £10,000 in a Stocks & Shares ISA and £10,000 in a Cash ISA. The Lifetime ISA (LISA) has its own separate allowance of £4,000 per year, which counts towards the overall £20,000 ISA limit. Junior ISAs (JISAs) for children have a separate allowance of £9,000 per year. Unused ISA allowance cannot be carried forward to the next tax year.
What is a Lifetime ISA and who should use one?
A Lifetime ISA (LISA) is a tax-advantaged savings account for UK residents aged 18–39. You can contribute up to £4,000 per year and the government adds a 25% bonus on top — worth up to £1,000 per year. The money can be used for two purposes: buying your first home (property must be £450,000 or less) or retirement from age 60 onwards. If you withdraw the money for any other reason before age 60, you pay a 25% withdrawal penalty — which effectively returns the bonus and charges you a further 6.25% penalty on your own contributions. LISAs are ideal for first-time buyers saving for a deposit or younger savers who want a bonus on top of their pension savings.
Stocks & Shares ISA versus Cash ISA — which is better?
The choice between a Stocks & Shares ISA and a Cash ISA depends mainly on your investment horizon and risk tolerance. Cash ISAs are low risk and provide guaranteed returns (currently 4–5% with competitive providers), making them suitable for short-term savings or emergency funds. Stocks & Shares ISAs invest in the stock market, historically returning around 7–9% per year over the long term (before charges), but with year-to-year volatility including potential losses. For goals more than 5 years away — such as retirement or a house purchase a decade hence — a Stocks & Shares ISA typically produces significantly better returns. For money you may need within 1–3 years, a Cash ISA protects you from having to sell at a loss. Many investors use both: a Cash ISA for short-term savings and a Stocks & Shares ISA for longer-term growth.
Can I have multiple ISAs at the same time?
Yes. Since the 2024/25 tax year you can subscribe to multiple ISAs of the same type in a single tax year — a rule change from previous years when you could only open one of each type per year. However, your total contributions across all ISAs must not exceed the £20,000 annual allowance (£4,000 if you also use a LISA). If you transfer money between ISAs using an official ISA transfer, it does not count towards the annual allowance. It is important to use the ISA transfer process when moving money between providers — withdrawing cash and redepositing will use up your current year allowance.
UK ISA Calculator 2024/25 — Project Your Stocks & Shares, Cash & Lifetime ISA Growth
Why ISAs are the UK's most powerful tax-free savings tool
Individual Savings Accounts (ISAs) are the cornerstone of tax-efficient saving and investing for UK residents. Every year you can shelter up to £20,000 from income tax and capital gains tax inside an ISA wrapper. Unlike pensions, you can access your ISA money at any time without penalty (except the Lifetime ISA). The tax-free compounding effect over long periods is dramatic: on a £20,000 annual contribution growing at 7% per year, the ISA wrapper saves a higher-rate taxpayer tens of thousands of pounds in tax over a decade compared with a taxable account. ISA income and gains do not even need to be declared on your tax return. The £20,000 allowance applies fresh each tax year, so consistent use over time enables substantial tax-free wealth accumulation. With over 22 million ISA accounts held in the UK, they remain the most popular individual savings product.
Maximising your ISA allowance: a year-by-year strategy
Getting the most from your ISA requires consistent, early contributions. Investing at the start of the tax year (April 6) rather than the end (April 5) gives your money 12 extra months of tax-free growth — over a lifetime this "early bird" strategy can add thousands to your final balance. Setting up a monthly standing order ensures you invest regularly without needing to remember. Couples should each use their individual £20,000 allowance, effectively doubling the household tax-free envelope to £40,000 per year. For those with children, a Junior ISA allows a further £9,000 per year per child, starting them on a tax-free investment journey from birth. When you have built up a significant ISA balance, the tax saving becomes increasingly important as dividends and interest that would otherwise be taxable accumulate free of charge within the wrapper. Always shop around for the best ISA rates and platform charges, as fees can significantly erode returns over a 20–30 year period.
Learn more from an authoritative source:
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Results are estimates for informational purposes only and do not constitute professional financial, medical, legal, or technical advice. Read full disclaimer →