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ISA Contribution Split Planner (UK)

Compare different ways to split your ISA contributions between cash and investments over time.

No sign up. UK focused. Results are estimates only.

Not financial advice

ISA Contribution Split Planner

One-off contribution (optional)

Monthly contributions (£)

Time horizon (years)

Risk profile

ISA contribution split scenarios

Scenario A

Lower volatility, steadier returns

Scenario B

Higher growth potential over time

Outcomes

Want to explore a different approach? Adjust your allowance strategy with the ISA Allowance Optimiser

ISA Plan provides educational planning tools. No financial advice is given.

How to use the ISA Contribution Split Planner​

  1. ​Enter your contributions (and any lump sum)

  2. Choose your time horizon and risk profile

  3. Compare contribution split scenarios

What people often do next

Review & refine

Users often revisit their risk profile or contributions split to explore more cautious or growth-focused approaches.

Check allowance usage

After deciding how to split contributions, many users check how much ISA allowance they still have available this tax year.

Explore growth potential

Once a split feels right, users often explore how contributions could grow over time under different return assumptions.

Advanced planning

Advanced ISA Planner

For those who want a deeper view, the Advanced ISA Planner helps you explore longer-term scenarios side by side across different splits, combine different ISA types, 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.

Advanced-planner-preview-example

ISA Contribution Split Planner FAQ's

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