What is compound interest and how it can benefit you?

We look at compounding, one of the most important concepts for beginner investors to grasp.

| 3 min read

Compounding is one of the most important concepts for beginner investors to grasp. It’s the gradual but powerful effect of getting returns on your money and returns on your returns. The effect is to magnify your gains over time, and it’s what makes time the most powerful ally an investor has.

Imagine two people each invest £1,000 and get a return of 5% a year. This is just by way of an illustration; you are unlikely to get a uniform 5% in income and/or capital gain, but it keeps things simple. The first person takes the 5% they made out each year and spends it, leaving just the £1,000 invested, the other keeps everything invested – their original money and all their gains. The table below shows what happens to their overall returns over time.

Overall returns over time table

In the early years there’s not much difference to how much the investors have made. Yet over longer periods the power of compounding kicks in and the gains become larger and larger the longer the money is left alone. Here’s how it looks in a chart:

Overall returns over time graph

This so-called ‘miracle of compounding’ is just straightforward maths, but its remarkable effect reputedly led Albert Einstein to refer to it as the ‘eighth wonder of the world’. Compounding is also responsible for the success of many businesses that invest for growth, as well as the large sums accumulated by famous investors such as Warren Buffett.

Buffett figured out the power of compounding at an early age when he bought a pinball machine and cut a deal with a local barber to install it in his shop. It was an instant hit, but rather than resting on his laurels he used his share of the money people spent on the first machine to buy another. He was then earning twice as much money and was able to buy a third and a fourth machine even quicker. Soon enough he had dozens of pinball machines in barbers’ shops all over town.

You don’t need a business mind or a smart strategy to benefit from compounding though. Investors harnessing returns in the form of capital gains and dividends benefit too. The essential ingredients are time and patience.

Three ways you can take advantage of compounding

  1. Start early. The longer period you invest for the more powerful compounding becomes. Take two investors, both investing for retirement in 40 years' time. One starts investing £100 per month right away, the other does nothing for 20 years, but then invests £300 per month. The investments chosen both grow by 5% per year after charges. At retirement, the first investor will have spent £48,000 on their monthly contributions and the second investor £72,000. Yet despite having spent much less, the first investor's retirement pot would be worth £152,252 compared to the second investor's £123,310.
  2. Don’t take too little risk. The greater the return the greater the effect and earning next to nothing on interest cash in the bank isn’t going to make compound work for you to a significant degree.
  3. Avoid taking excessive risk and sustaining large losses. Making a profit consistently is easier said than done, but a really big loss can be hard, if not impossible, to recover from. This is why taking a sensible amount of risk through a diversified approach is so important. That won’t mean losses are eliminated but it should limit the downside and allow a ‘slow and steady’ approach to keep working given enough time.

Nothing on this website should be construed as personal advice based on your circumstances. No news or research item is a personal recommendation to deal.

What is compound interest and how it can benefit you?

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The information in this article is based on our understanding of UK Legislation, Taxation and HMRC guidance, all of which are subject to change. The tax treatment of pensions depends on individual circumstances and is subject to change in future. This article is solely for information purposes and does not constitute advice or a personal recommendation.

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