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🇬🇧 ISA Calculator (UK)

Project your tax-free ISA growth — Stocks & Shares, Cash, or Lifetime ISA. £20,000 annual limit and 25% LISA government bonus applied automatically.

UK-only calculator. Region locked to United Kingdom. Figures use the 2026/27 ISA allowances: £20,000 total / £4,000 Lifetime ISA cap / 25% government bonus.
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Tax-Free Balance
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Total Contributions
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Total Tax-Free Growth
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Government Bonus (LISA)
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S&S vs Cash ISA Difference

Year-by-Year Breakdown
Year Age Contribution Gov Bonus Year-End Balance
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Methodology & Sources

This calculator models the UK Individual Savings Account (ISA) using the 2026/27 tax-year rules. The annual ISA allowance is £20,000 spread across Stocks & Shares, Cash, Innovative Finance, and Lifetime ISAs. The Lifetime ISA has a separate annual cap of £4,000 (counted within the £20k total) and attracts a 25% government bonus on contributions until age 50. LISAs can only be opened between ages 18 and 39. All growth and withdrawals within an ISA wrapper are free of UK income tax and capital gains tax.

Last verified: May 2026.

Frequently Asked Questions

What's the ISA allowance for 2026/27?
£20,000 across all your ISAs combined for the 2026/27 tax year. You can split it between Stocks & Shares, Cash, Innovative Finance, and Lifetime ISAs in any proportion. The Lifetime ISA itself caps at £4,000 of that £20,000.
What is a Lifetime ISA (LISA)?
A Lifetime ISA gives you a 25% government bonus on contributions up to £4,000 a year (so up to £1,000 free per year). You can use it for a first home up to £450,000, or withdraw penalty-free from age 60. Withdrawals for any other reason carry a 25% penalty — which actually loses you slightly more than the bonus you received.
Stocks & Shares ISA vs Cash ISA — which is better?
For investment horizons of 5+ years, Stocks & Shares historically beat Cash ISAs by a wide margin (S&P 500 ~7% real return vs cash ~0–2% real). For short-term goals or emergency funds, Cash ISAs win because the principal is safe. This calculator shows the typical gap on your specific numbers.
Can I have both a Stocks & Shares ISA and a Cash ISA?
Yes. You can pay into one of each type per tax year (S&S, Cash, Innovative Finance, LISA) as long as the total across all of them stays under £20,000. From April 2024 you can also split contributions between multiple S&S or multiple Cash ISAs — a rule change that simplified things considerably.
What happens to my ISA if I die?
Your spouse or civil partner inherits an Additional Permitted Subscription (APS) equal to the ISA's value at your death — they can shelter that extra amount in their own ISA on top of the normal £20k. The investments themselves remain in the estate.
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