ISA projection
Projected balance, total contributions, and bonus where relevant.
BalancePaid inLISA bonus
ISA Calculator
Project ISA growth with monthly savings, annual return, allowance checks, and Lifetime ISA bonus modelling.
Projected ISA value£150,554After 15 years
Total paid in£98,000
Growth and bonus£52,554Estimated return
Allowance check
Annual contribution£6,000
2026/27 ISA allowance£20,000
Allowance headroom£14,000
Lifetime ISA bonus modelled£0
Assumptions
Calculation notes
- Uses the selected 2026/27 overall ISA allowance of £20,000.
- Lifetime ISA eligibility, withdrawal penalties, age limits, provider rules, and investment risk are not fully modelled.
- This is a planning estimate, not savings or investment advice.
Savings projection
How the ISA scenario is built
The ISA view separates money paid in from assumed growth so the result does not look more certain than it is.
Savings model
The ISA calculator compounds starting savings and regular contributions using the selected growth, fee and time assumptions.
Where Capital Gains Tax context is shown, the calculator uses the selected tax-year rules to keep ISA sheltering and taxable investing comparisons transparent.
ISA pathstarting balance + regular contributions -> compound growth over time -> projected ISA value
Monthly saving example
Example: monthly ISA saving
- Starting ISA: GBP 5,000
- Monthly contribution: GBP 250
- Growth and fee assumptions: selected by user
Result: The chart shows how contributions and growth build the projected pot over time.
The result is a scenario, not a market forecast; compare cautious and optimistic growth assumptions.
Comparing ISA scenarios
- Contribution habit often matters more than a single growth assumption over shorter horizons.
- ISA allowances and tax treatment can change, so check the rules year and official limits before acting.
Content reviewed: 7 September 2026.
Guide
ISA Calculator notes
Estimate how Cash ISA, Stocks and Shares ISA, or Lifetime ISA saving might build over time under simple assumptions.
Choose the rules year that matches the scenario you are checking.
Review the calculation notes where rules, tax years, thresholds, or eligibility affect the result.
FAQs
ISA Calculator FAQs
What is the ISA Calculator for?
Estimate how Cash ISA, Stocks and Shares ISA, or Lifetime ISA saving might build over time under simple assumptions.