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ISA Calculator UK – Calculate your ISA returns

Our ISA calculator is a great way of understanding how much your ISA could be worth in the future.

Whatever your investment goals, our ISA calculator can help you identify how much you might need to invest each month to achieve your investment goal, or indeed how long it might take you to reach your goal with your current monthly investment.

It’s important to consider that this is intended as a guide only, and investment growth is impossible to predict with any accuracy.

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Interactive Investor

  • The number one choice for stocks and shares ISA
  • Open an ISA account for £9.99
  • Contribute as little as £25 per month

Important information - investment value can go up or down and you could get back less than you invest. If you're in any doubt about the suitability of a Stocks & Shares ISA, you should seek independent financial advice. The tax treatment of this product depends on your individual circumstances and may change in future. If you are uncertain about the tax treatment of the product you should contact HMRC or seek independent tax advice.

How to use our ISA calculator

Follow these simple steps:

  1. Input the amount of single or regular payment
  2. The year-on-year growth you’re expecting*
  3. Enter the number of years you might keep the portfolio.

* The default setting is 5%. it’s neither an average nor recommended value. We can’t predict investment returns higher or lower than this. If you want to see how another level of investment return could affect what you get back, change the expected rate.

The numbers are approximate and based on the percentage of expected growth rate selected.

The ISA calculator serves as a tool to help you make decisions. Never consider it as a prediction of performance in future, nor a guarantee.

Initial Payment
Regular Payment Monthly Annually
Year-to-year portfolio growth
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Year-to-year portfolio growth
{{num_yrs}}/20yrs

Investment growth over time £{{finalTotal}}

What are the tax rules?

Money you earn in a stocks and shares ISA is completely free of any capital gains tax, making this the most tax efficient way of saving towards a financial goal.

There are however, certain tax allowances that you should be aware of when saving into a stocks and shares ISA.

Every person in the UK has an ISA allowance. This is the amount of money you can save into an ISA in any one tax year. The current ISA allowance for 2021-2022 is £20,000.

Any unused allowance can not be carried over so it’s important to maximise your allowance where possible.

Tax treatment is reliant on individual circumstances and all tax rules may change in the future.

Is a Stocks and Shares ISA right for you?

It is important that you take your personal circumstances into account when deciding whether a stocks and shares ISA is right for you.

All investments come with a degree of risk, and the level of risk that is suitable for you will largely depend on how much of your investment you are willing to lose. The more risk you assume, the higher the potential gains will be.

Do you have enough savings to comfortably lock your ISA investments away for a minimum of five years? You should be able to access 3 to 6 months of salary to cover expenses that may arise in the event of an emergency.

Locking your investments away for a minimum of five years not only allows you to enjoy compound growth, but also facilitates riding out any volatility in the marketplace.

If you decide that investing isn’t for you, then you may want to consider putting your savings in a cash ISA. Cash ISAs will often attract a small amount of interest and any gains are still protected from the taxman.

Should you be unsure whether a cash ISA or stocks and shares ISA is best for your individual circumstances, then you may want to seek financial advice.

How to invest into an ISA

The first step to investing into an ISA is to find an ISA provider that is right for you. This will largely depend on whether you are comfortable managing your own investments or would rather a ‘set it and leave it’ service. You will also need to take into account whether you are investing a lump sum payment, or would rather invest regular monthly payments.

I have taken the time to compare the top ISA providers available for you, including their fees and investment options, so you can make an informed decision on which stocks and shares ISA suits you.

All my recommendations have been researched and are authorised and regulated by the Financial Conduct Authority.

ISA calculator FAQs

How much interest will I earn with an ISA?

Only a cash ISA will pay you interest, and whilst this may eliminate your exposure to risk, interest rates are notoriously low at the moment. At the time of writing, you can expect to earn up to 1.76% on a fixed term ISA and 0.65% on an easy access ISA.

What is important to consider is that at the time of writing the UK inflation rate stands at 5.4%, meaning your cash will actually be losing value in a cash ISA at present.

Are ISAs worth it in the UK?

The answer to this question largely depends on whether you are earning over the personal allowance on your income. The personal allowance is a sum of money that you can earn in any given tax year without having to pay tax on that income. The standard Personal Allowance for 2021/22 is £12,570.

Anything above the personal allowance will be taxed at your normal income rate, unless you have your savings in an ISA. In this instance, your gains will be completely free from tax.

Even for people who are currently earning less than their personal allowance, an ISA is a good idea, as should you start to earn in excess of your personal allowance, you may struggle to move all your savings across to an ISA in one year whilst still remaining within the ISA allowance.

How much do ISAs grow?

This will vary according to your investment choices and fund charges. In addition it is important to remember that the stock market is volatile and past performance is never a reliable indicator of future performance.

To illustrate this, the average stocks and shares ISA experienced a growth of -13.3% in the 2019/20 tax year. However, in stark contrast, for 2020/21 this growth changed to 13.55%.

This is why it is always recommended that you are prepared to remain invested for a minimum of five years in order to ride out any volatility.