Frequently Asked Questions
For the current allowances, limits and dates with their gov.uk sources in one place, see ISA rules at a glance.
ISA Calculators FAQs (UK)
Both scenarios use the same contribution amounts and time period. You can then compare the estimated outcomes side by side using different growth assumptions or investment approaches.
Yes. Both scenarios use the same total contributions so you can isolate the impact of investment strategy alone.
Yes. The growth-focused scenario assumes higher exposure to market movements, meaning values can rise or fall over time.
No. This planner provides illustrative estimates only and does not account for personal circumstances or tax considerations.
The lower-growth option assumes lower volatility and lower growth, while the growth-focused scenario has higher exposure to market movements, so its values can rise or fall more. Some investors value lower volatility, especially over shorter time horizons or when nearing a financial goal. Neither option is a recommendation, and values can fall as well as rise.
A Lifetime ISA (LISA) is a UK savings or investment account that helps you save for your first home or retirement, offering a 25% government bonus on your contributions.
The government adds a 25% bonus on eligible contributions, up to a maximum bonus of £1,000 per tax year. This calculator includes the bonus in its estimates.
Yes. You can contribute up to £4,000 per tax year to a Lifetime ISA. Contributions count towards your overall ISA allowance.
A withdrawal incurs a 25% government withdrawal charge, often called the Lifetime ISA penalty, unless it is to buy a first home, is made from age 60, or is because of a terminal illness (less than 12 months to live). There is no charge if the account holder dies: the Lifetime ISA ends on the date of death. This calculator shows what you would get back if you withdrew the whole estimated balance early and paid that charge; it does not model partial withdrawals or the timing of a withdrawal.
No. The calculator uses a constant assumed return to illustrate potential growth. Actual investment values can rise or fall.
No. This Lifetime ISA calculator is for educational planning only and does not provide personal financial advice.
This calculator estimates how a Stocks and Shares ISA could grow over time based on your contributions, time horizon and assumed rate of return.
No. Investments can rise and fall in value, and actual returns may be higher or lower than shown. This tool provides estimates only.
The rate entered is an assumption that depends on the ISA type being modelled. A lower rate gives a lower projected balance and a higher rate gives a higher one, and a higher rate can overstate potential growth. Actual returns are not guaranteed and can be lower.
No. ISAPlan gives you educational calculators and estimates only. You can use them to explore ISA ideas, but they do not replace advice from a regulated financial adviser.
Yes. Many users combine this with the ISA Allowance Checker or Contribution Split Planner to build a more complete ISA plan.
The Cash ISA Calculator estimates how your balance could grow over time, considering your initial deposit, monthly contributions, and an assumed interest rate. Interest is added monthly, so you can also read the result as the monthly interest on your balance added up over one, five or more years.
Cash ISA rates can change over time and are not guaranteed. This calculator uses a constant rate for illustration.
No. The calculator shows the estimated balance in nominal terms. Inflation can reduce the real purchasing power of savings.
No. Cash ISAs are typically tax-free, but individual circumstances can vary. This tool is for educational planning only.
No. ISA Plan provides educational calculators and planning tools. Results are estimates only and not financial advice.
This tool compares different ways to split ISA contributions between Cash ISAs and Stocks & Shares ISAs, based on your time horizon and risk preference.
No. The planner shows illustrative scenarios to support decision-making. The most suitable option depends on your personal circumstances and tolerance for risk.
No. Any outcomes shown are estimates only. Investments can go down as well as up, and past performance is not a guide to future returns.
No. The planner focuses on contribution allocation and high-level growth assumptions. Fees, inflation, and tax treatment vary by provider.
Yes. Many investors adjust their ISA allocation over time as goals, risk tolerance, or market conditions change.
The ISA Allowance Checker shows how much of your annual ISA allowance you have remaining and the average per month if that amount were spread evenly over the months left in the tax year.
No. This tool does not model investment returns or growth. It shows only how much of your ISA allowance is left in the current tax year and the average per month if the remaining amount were spread evenly.
No. The calculator shows an average monthly figure. You can invest more in some months and less in others, as long as your total contributions stay within your ISA allowance.
This calculator uses the current UK ISA allowance of £20,000 per tax year. Allowance limits may change in future tax years.
No. This tool does not include platform fees, fund charges, or investment performance. It is designed for allowance planning only.
No. ISA Plan provides educational calculators and planning tools only. The results are estimates and do not constitute financial advice.
It is the yearly rate the calculator applies to the balance. For a Cash ISA it is the interest rate; for a Stocks and Shares ISA it is an assumed return, which is what makes this an ISA growth calculator rather than a forecast. Investments can go down as well as up, so this calculator is for scenario planning only.
Not by default. Fees and inflation can reduce real-world outcomes.
Yes — the calculator supports both, so you can use it as an ISA savings calculator for regular monthly deposits, for a one-off lump sum, or for the two together.
It compares the contributions you enter with the current UK ISA allowance of £20,000 per tax year. That helps you see how much allowance you may have left.
No. This tool is educational and provides estimates only.
An ISA (Individual Savings Account) is a UK tax-efficient way for you to save or invest. Any interest, dividends, or growth within an ISA is free from UK income tax and capital gains tax, up to your annual allowance.
Yes. You can use the core ISA calculators for free, with no sign-up required. Optional advanced planning tools may have a one-off fee.
The results are estimates based on the information you enter and standard UK tax-year assumptions. They’re designed to help you explore scenarios, not to provide personalised financial advice.
Yes. You can hold more than one ISA. You still need to follow the current rules for ISA types and total contributions each tax year.
No. ISAPLAN provides educational tools and calculators to help you understand how ISAs work. If you’re unsure about your situation, you may wish to speak to a regulated financial adviser.
The free calculators are ideal for quick calculations and simple scenarios. The Advanced ISA Planner is designed for users who want to explore multiple tax years, combine different ISA types, or compare scenarios in more detail.