Rule of money. Rule of 72

To become a successful investor, we must be constantly thinking how to compound our money so it can keep growing, growing and growing to create wealth for us. One very very powerful and simple rule to calculate how fast the money compound is called RULE of 72, or I call it rule of money. This rule is invented by the greatest scientist all time. Mr Albert Einstein. I think this rule is even more profound than E=MC^2!

Here's how it works,

Let's say you invest 1000 dollar into a investment account that earn you annual 4% of interest, you wonder how long it will takes for the initial capital to double? Rule of 72 can help you determine it quickly. You use 72 divided by 4, you get 18. This means that after 18 years from the time you invest, your initial capital will double! In our example, after 18 years, your money will become 2000. Please note that we assume we pay no tax and we reinvest our interest each year.
Now, look at the case on the top of this post. Imagine a person have 10,000 to invest at age 30, he put in some kind of tax deferred account which allow money to grow without paying tax until he reach 66 for retirement. Can you see how the small increase of the of annual interest can product A BIG BIG BIG difference over a long period of time? This is the power of compound interest! What if the annual interest is 18%, can you figure how much money will that be at age 66?