You should have no interest in interest, but plenty in the power of compound returns.

Einstein Quote- "Compound interest is the eighth wonder of the world. He who understands it, earns it... he who doesn't... pays it.

Published on January 2021

Albert Einstein’s wisdom didn’t stop at physics. In a lesser-known quote he called compound interest the ‘eighth wonder of the world’. For those that understand compounding, the reason why is obvious.


However, we can’t all be Einstein. Compounding is difficult for most of us humans to wrap our head around intuitively. For those that don’t yet appreciate this huge and undeniable, I suggest you read on.


So what exactly was Einstein referring to as the eighth wonder of the world? How can we harness this to help ensure our long term financial success.


The eighth wonder of the world


Warren Buffet is another household name. He became famous through his reputation as a visionary investor and, of course, being one of the richest people on the planet. His current wealth is estimated at around $130 billion.

There is no disputing that Buffett is a great investor. There are literally hundreds of books that claim to teach you how to follow in his footsteps. However, almost none of them will tell you about Buffett’s secret to the staggering amount of wealth he holds today. But the real answer is incredibly simple: time.

Warren Buffet’s wealth at different ages

Warren Buffet’s wealth at different ages
Buffett has made over 90% of his fortune since turning 65

Buffett made his first investment at just 11 years old, and he is still going strong at the age of 93. This means he has held investments for over 80 years, one of the longest periods of any single person on the planet! Although Buffett has been incredibly successful, his wealth did not reach the levels that would make him a household name until after around 50 years of investing.

Picture of Warren Buffett sitting in his office
Buffett in his office, where he has worked for over 60 years

This isn’t because Buffett suddenly became a better investor in his 50’s. In fact, his outperformance of the market has been declining for decades and he has even underperformed in recent years2. Buffett’s massive accumulation of wealth is simply down to the fact that he has consistently been earning a good return on his money for the best part of a century. He has benefited from the full power of compound returns.


If Buffett started investing when he was 25 instead of 11 and earned exactly the same level of return until his retirement at 65, he would be worth $11.7 million. This is still very good going for someone who essentially started from scratch, but is a mere 0.013% of his current net worth.

Those who understand it, earn it, those who don’t, pay

Unfortunately, most of us wont have started as early, and may not live as long, as billionaire Buffett. However, the important message to take from this longer you hold money earning a positive rate of return, the bigger the gains you make every year.

At lower rates of returns, this difference is pretty lacklustre. Earning 1% return per year on £1,000 earns you £10 in year 1 and £14.74 in year 40. However, as the rate gets larger, this effect multiplies. At 10%, £1,000 grows 45x to over £45,000. 10% per year would yield over £4,000 every year by year 40, that’s 4 times the initial £1,000! 30 or 40 years may seem like an unrealistic amount of time, but when considering saving for retirement, this is a reasonable time horizon.

The growth of £1,000 earning different rates of return over 40 years

A graph showing The growth of £1,000 earning different rates of interest over 40 years

Definition of inflation- The decline of the ‘purchasing power’ of a currency over time. This is driven by prices of goods and services increasing, meaning the same amount of money can buy less. For example, inflation of 2% in a year means the same amount of money can, on average, buy 2% less goods and services at the end of the year than it could at the start.

While it was possible to get a good rate of interest on your money in Einstein’s day, the chances of earning anywhere near even 5% per year, after inflation, on your money in a bank account or from bonds is currently slim to none. In fact, as interest rates are often less than inflation, keeping your money in a bank account means you are effectively paying to save your money.


However, interest isn’t the only possible way to benefit from the effect that Einstein is referring to. Investing is another. While earning interest consistently above inflation per year on your savings in the bank or an ISA is unlikely, expecting this much from investing in shares and other assets is perfectly reasonable by historical standards. If you earn such returns for long enough, the full benefits of compounding returns, similar to those you saw on the graph above, can be felt.

It is important to understand that investing is riskier than earning interest. Market crashes can last a year, two or in rare cases even longer. However, providing you are able to leave your money invested for long enough, the market should recover and surpass previous levels, if the entire history of the stock market is anything to go by, that is. It is sensible to plan ahead with investing, ensuring that you won’t need any money you put away for at least 5 years. Investing money which you might need may force you to sell investments when the market is down and crystallise your losses. If you are not risking money you may need to call upon what really matters is the long run rate of return, not their short-term volatility.

For instance, the global equity market has had four years since 2010 where it finished below where it started, 2011, 2018 and 2022. It also contained some of the most severe market swings since records began last year as the market reacted to the news of the pandemic. However, despite this volatility, the global equity market has posted an average return of 10.1% per year over the last 10 years (to February 2024)1. Money earning this rate of return will double in value around every 7 years.

What does this mean for you?

Buffett is perhaps the best example to demonstrate how great benefits of the compound returns from investing can be. While you may not make billions, getting a good return on your money rather than letting inflation eat it away is crucial. It means the money you have already have will work towards your goals for you, and the longer it is left to work, the more you will benefit.

It is particularly important to consider investing when it comes to retirement. It may seem distant, but it is the best opportunity you have to earn compound returns on your money precisely because it is such a long way away. Compound returns mean generally that, the earlier you invest, the less you have to invest in total to have the same amount by retirement. Be on the lookout for my follow up article, which will look at this topic in more detail by telling three different stories of people preparing for retirement.


Do you want to start investing but are not sure where to begin? I have a new series of articles which should cover everything you need to know. You can find my first post here.

Risk warnings


This article is distributed for educational purposes and should not be considered investment advice or an offer of any security for sale. The above contains the opinions of the author but not necessarily the Firm and does not represent a recommendation of any particular security, strategy, platform or investment product. Information contained herein has been obtained from sources believed to be reliable but is not guaranteed.

This article was produced for educational purposes and aimed at UK residents.

Past performance is not indicative of future results and no representation is made that the stated results will be replicated.


1Measured by the performance of the MSCI ACWI, not including the effects of inflation [LINK]

22019, Forbes, After a decade of underperformance, Warren Buffett should retire on top [LINK]


Share this content