Albert Einstein had once called power of compounding as the eighth wonder of the world. This is one investment principle which makes money making simple. There are two facets of power of compounding which if you follow as an investor, creating wealth becomes easy. First is to start investing early and giving time to your investment and second stay invested, do not withdraw money in between and let it grow.
In simple terms compounding is nothing but reinvestment of interest/income earned at the same rate so that interest/income earned also generates additional return at the same rate in future. Let me explain this with simple example :
If you invested Rs. 1,000/ in an instrument giving 10% return in a year. At the end of year 1, value will go to Rs. 1,100 and in year 2 you will earn return on Rs. 1,100 and not on original investment of Rs. 1,000/.
But why is it so important in world of investment and how can it create wealth for investors ?
Let’s try to understand this with simple story of chess & grain. Chess was invented by Grand Vizier Sissa and then he gave it to a king in India. The king offered anything in return; Vizier said that he would be happy merely to have some wheat: one grain for the first square of the chessboard, two grains for the second square, four for the third, eight for fourth and so on. The king was amused by the ‘small thinking’ of Vizier but the king could not fulfill the desire of the inventor of chess. Why? The number of grains for the whole board = 18,446,744,073,709,551,615. This is more wheat than in the entire world; in fact, it would fill a building 40 km long, 40 km wide, and 300 meters tall. So, the moral is if one uses the ‘Power of compounding’ smartly, then becoming rich is not a dream.
Let me explain the same concept in investment parlance. Let us understand a story of a tortoise and hare. The hare saves Rs. 10,000 every year for the first 10 years. After that he saves nothing. However, he compounds his money at the rate of 15% for 30 years. The tortoise starts at the year 11 and keeps saving Rs. 20,000 every year (double of what hare saved) for the next 20 years. Like the hare, he too compounds his savings at 15% every year. So hare invests only Rs. 1 lakh and tortoise invests Rs. 4 lakhs. Let’s tally the score at the end of 30 years. Tortoise makes a respectable Rs. 23,56,202 whereas the hare makes Rs. 38,21,468! This is nothing but power of compounding for hare and cost of s15.5 lakh for starting late for tortoise.
So there are two simple logic of generating compounding impact on your portfolio:
 Start investing early in life. No matter how small that investment is but start investing whatever small amount you can save. Ideally starting point should be 1st month of pay cheque of your life. So as soon as one starts earning, he/she should start investing.
 Let your investment grow consistently without doing unnecessary withdrawals in between.
The same logic of compounding applies to retail investors approach. No matter how small you start with, important is to start investing early so that your money gets time to compound over a period of time. As investor starts early and has time on his side, he can look at higher return potential asset class like equity to generate positive real return and create wealth over a period of time. Important is not how much you invest, more important is for how long you stay invested.
Rule of 72 might help you in understanding this concept. Rule of 72 gives you doubling period. In short it explains how long your investment will take to double. This rule says that to know doubling period you divide compound rate of return into 72 and you get doubling period in number of years. e.g. if your investment generates 12% return then 72/12 = 6 is the number of years require to double your money.
So if you park your money in fixed deposit giving 9% return you will require 72/9 = 8 years to double your money whereas if you park your money in mutual funds generating 15% return you can double your money in 4.8 years.
(Initial investment of Rs. 1 lakh) 

As you can see from the above graph, investment of Rs. 1 lakh will grow above Rs. 2 lakh by 5th year at 15% compounding while it takes 8 years in compounding at 9%.
As Albert Einstein said, ‘compounding is something one who understands earns it and one who doesn’t understand pays it’. Remember compounding works best with equity asset. That may be the reason why world’s richest men list include people who have created wealth by taking advantage of compounding with their equity investment.