ISA Calculator

Up to £20,000 between 6 April 2026 and 5 April 2027. You can put it all in one ISA or split it across cash, stocks and shares, Lifetime and Innovative Finance ISAs. Anything you don't use is lost at the end of the tax year.

From 6 April 2027, under-65s can only put £12,000 a year into cash ISAs. The overall allowance stays at £20,000, so the other £8,000 would need to go into a stocks and shares ISA. Over-65s keep the full £20,000 cash limit.

Paying in £1,666 a month, a full ISA could grow to about £245,318 after 10 years at 4%, or £288,359 at 7%. After 20 years that becomes £611,047 at 4% or £867,864 at 7%. Investment returns aren't guaranteed.

Yes. You pay no tax on interest, dividends or gains inside an ISA, or when you take money out. Outside an ISA, interest above your Personal Savings Allowance (£1,000 for basic-rate taxpayers, £500 for higher-rate) is taxed.

For a cash ISA, use your account's interest rate. For a stocks and shares ISA, 5 to 7% a year is a common planning figure, but returns aren't guaranteed and can be negative. You can add platform fees in the Advanced tab.

Yes. Since April 2024 you can pay into more than one ISA of the same type in a tax year, as long as the total stays within £20,000.