Power of Compound Interest

Thursday, September 01, 2005
A quick financial lesson.

Let's say you decide to invest in a Roth IRA, my favorite investment vehicle. You decide to start one today and invest the maximum $4,000 every year. You invest it wisely in an index fund that follows the total stock market which has historically returned 10% a year. In 40 years, your $4,000 a year, ($160,000 in principal payments) turns into $1,947,407.24, All of it tax free.

Now imagine if you were a good little saver and have saved the last 4 years. With a modest gain over the last few years you have $17,000 in your account. With the same investment strategy above you now have at the end of 40 years 2,716,814.59, All of it tax free. That is almost $800,000 difference for saving a little bit earlier. That $17,000 turned into $800,000!

Still not convinced? How about this? You do the above strategy from the ages of 25-35 and then stop. So for 10 years you invest $4,000 and then nothing after that. By the age of 65 you will have an account worth $1,223,633,58. Your $40K turned into $1.2 Million.

Or instead, you do nothing from the age of 25-35 and instead save from the age of 35-65 with the same strategy. Your final balance will be $723,773,70. Your $120K turned into $720K. Not bad until you consider that that's a half-million dollar difference from the previous example of $1.2 Million! And you put in 1/3 the amount in principal and saved 3x as long!

The lesson? Save early, save often. I can't stress this enough to my young friends. I know it is hard to save money now, but in the long run, it makes a BIG difference.


susan said...

Love compounding. I thought it was great when my 15 year old came home and said "hey, Mom, do you know about compounding interest?" I told her I did and she told me she needed to start a retirement account. So we started one. And when she's 45 she's gonna be rich!

T said...

Yeah, if you started your daughter when she was 15 she is going to be loaded by the time she retires! Good Job!