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Stocks & Shares ISA Calculator (UK)

Estimate how ISA investments could grow over time based on your contributions, an expected return and your time horizon.

No sign up. UK focused. Results are estimates only. Investments can go down as well as up.

Not financial advice

Stocks & Shares ISA Calculator – Estimate Tax-Free Investment Growth

Use this Stocks & Shares ISA calculator to estimate how investments inside a UK ISA could grow tax-free over time. Unlike a Cash ISA, a Stocks & Shares ISA can rise and fall in value, but it may offer stronger long-term growth potential through funds, shares and diversified portfolios.

This tool is ideal if you’re investing for 5+ years and want to model how monthly contributions, an initial lump sum and an assumed annual return could affect your final ISA value. Adjust the inputs to see projected growth over your chosen time horizon.

If you’re comparing options, you may also want to use our Cash ISA Calculator for savings-style interest projections. For deeper modelling — including risk profiles and side-by-side scenario comparisons — explore the Advanced ISA Planner.

Stocks & Shares ISA Calculator

Initial lump sum (£)

Monthly contributions (£)

Time horizon (years)

Expected annual return (%)

Estimated Stocks & Shares ISA value after X years

£-

Estimate value

£-

Total deposited

£-

Interest earned

Figures shown are rounded to the nearest pound

Returns are estimates only. Investments can go down as well as up.

Advanced planning

Advanced ISA Planner

For those who want a deeper view, the Advanced ISA Planner helps you explore longer-term scenarios, combine different ISA types, including cash ISAs, and model multiple tax years in one place.

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It's designed for users who want more flexibility and insight than a basic calculator can provide.

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  • Combine Cash and Stocks & Shares ISAs

  • Model multiple tax years and allowances

  • Adjust returns, contributions, and time horizons

  • Compare scenarios side by side

Free calculators remain avaliable. No subscription required to get started.

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How to use the Stocks & Shares ISA Calculator​

Use this Stocks & Shares ISA calculator to estimate how regular contributions and lump-sum investments could grow over time, based on your chosen time horizon and expected annual return.

  1. Add any initial investment and monthly contribution.​

  2. Choose time horizon and estimated annual return.

  3. Review projected outcomes.​

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What people often do next

Review contribution strategy

Many users adjust their monthly contributions over or time horizon to see how small changes affect long-term outcomes.

Check ISA allowance usage

After modelling growth, users often check how much of their ISA allowance they've already used this tax year.

Compare investing vs cash

Some users compare Stocks & Shares ISA growth with Cash ISA returns to understand the trade-off between volatility and certainty.

Stocks & Shares ISA Calculator FAQ's

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