Precis

ISA Calculator

Projects tax-free growth of a Stocks & Shares or Cash ISA, within the current £20,000 annual allowance.

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Assumes a constant growth rate compounded monthly — real markets go up and down. All growth and withdrawals inside an ISA are free of Income Tax and Capital Gains Tax, so this is your actual take-home projection, not a pre-tax figure.
Projected ISA value
£0
after 15 years
Starting balance£0
Total contributed£0
Tax-free growth£0
Final value£0

How much can I pay into an ISA?

The ISA allowance is £20,000 per tax year across all your ISAs combined (Cash, Stocks & Shares, Lifetime and Innovative Finance) — that works out to £1,666.67 a month if spread evenly. Everything inside the wrapper grows completely free of Income Tax, Dividend Tax and Capital Gains Tax, which is why an ISA and a normal investment account with the same growth rate end up worth very different amounts after tax. If you're saving specifically for a first home or retirement, the LISA Calculator covers the Lifetime ISA's 25% government bonus separately.

Frequently asked questions

Do I pay tax when I withdraw from an ISA?

No — withdrawals from an ISA are always tax-free, regardless of how much growth has happened inside it. That's different from a pension, where withdrawals are typically taxed as income above the tax-free lump sum.

What's a realistic growth rate to assume?

Cash ISAs broadly track the Bank of England base rate. Stocks & Shares ISAs have historically returned around 5–7% a year over the long run before charges, though any individual year can be sharply up or down — this calculator only shows a smooth average, not real volatility.

Can I have more than one ISA?

Yes, you can hold and pay into multiple ISA types in the same tax year (e.g. a Cash ISA and a Stocks & Shares ISA), as long as your total contributions across all of them don't exceed the £20,000 annual allowance.

Related searches

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