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Compound interest calculator

With compound returns, it’s less about how much you can afford to invest and more about how long the investment has time to grow. The basic concept of returns on returns is simple and can have powerful effects on a stocks and shares ISA or pension. Our handy compound calculator works on a monthly compounding period and can give you an estimate of the impact of compounding over your chosen timeframe.

Calculate the impact of compound returns

Enter your details

Your results at the end of the timeframe

Compound projection


Initial investment


Total additional contributions


Total returns


Final value


As with all investing, your capital is at risk. This calculator is not a reliable indicator of future performance and is intended as an aid to decision-making, not a guarantee.

Capital at risk. ISA rules apply

Other useful investment and tax calculators

Need help estimating your investment and tax calculations? We have a range of calculators available to help you gain clarity over your finances and plan for future investments. These calculations are for illustrative purposes only, but you can book a free call with our expert team anytime to discuss your goals and gain more detailed financial guidance.

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Most people ask us...

What are compound returns?

In the first year of investing, you may generate returns on your initial investment, while in the second year, you invest the capital (your initial investment) plus the returns to generate further returns on the total. Reinvesting any returns on your returns means your money can enjoy exponential growth. Of course, investing is subject to market ups and downs, and there’s a risk you’ll lose some of the money you’ve put in. However, by investing over a long timeframe, you give your investment time to make up for any losses.


For example, £100 invested with an expected return of 10% will generate £10 in the first year, £11 the second year and £12.1 the third year. The initial £100 will always generate a return of £10, but starting from the second year, you will generate an extra £1 from your past gains, and an extra £2.1 the third year. Hence, returns on returns.

How does the compound returns calculator work?

Our handy calculator works on a monthly compounding period, and calculates your total returns based on your return rate period and timeframe in years. Your results are based on the assumption that any returns, including dividends, are reinvested and any monthly contributions are maintained.

Why choose a Nutmeg stocks and shares ISA?

Sign up or transfer to a Nutmeg stocks and shares ISA in minutes and we’ll do the investing for you. Choose the investment style and risk level that works for you, log in from any device and keep track of how your ISA is performing. Globally diversified, transparent and designed by experts, we believe investing should be a straightforward and empowering experience. 

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Capital at risk. ISA rules apply

As with all investing, your capital is at risk. The value of your portfolio with Nutmeg can go down as well as up and you may get back less than you invest. ISA rules apply.