ISA Calculator: How Much Could Your ISA Grow?
Updated for the 2026/27 tax year (6 April 2026 – 5 April 2027)
Project the value of a Stocks and Shares ISA, Cash ISA or Lifetime ISA from your starting balance, monthly savings, growth rate and fees. Free, no sign-up. Nothing leaves your browser.
Year-by-year projection
| Year | Paid in | Bonus | Growth | Balance |
|---|
ISA allowances 2026/27
| ISA | Annual limit | Notes |
|---|---|---|
| All adult ISAs combined | £20,000 | Resets each 6 April; unused allowance is lost |
| Cash ISA | £20,000 (£12,000 from April 2027 if under 65) | Interest is tax-free |
| Stocks & Shares ISA | £20,000 | No tax on dividends or gains |
| Lifetime ISA | £4,000 | 25% bonus; open at 18–39, pay in until 50 |
| Junior ISA | £9,000 | Separate allowance for children under 18 |
Frequently asked questions
What is the ISA allowance for 2026/27?
£20,000 per person across all your adult ISAs. Up to £4,000 of that can go into a Lifetime ISA. The Junior ISA limit is £9,000 per child.
Is the cash ISA limit changing?
Yes. From 6 April 2027 you can only put up to £12,000 a year into cash ISAs if you are under 65. The overall £20,000 allowance stays, so the rest can go into stocks and shares. Savers aged 65 and over keep the full £20,000 cash limit.
How does the Lifetime ISA bonus work?
The government adds 25% to what you pay in, up to £1,000 a year on £4,000 of savings. You can open one aged 18 to 39 and pay in until 50. Withdrawals other than for a first home up to £450,000 or after 60 lose a 25% penalty.
Do I pay tax on ISA growth?
No. Interest, dividends and capital gains inside an ISA are free of UK tax, and withdrawals are tax-free too.