compound interest mdj

The mantra of Million Dollar Journey is to build wealth through saving and investing.  As this is my belief of the easiest way for regular working folk (like our family) to build serious wealth to someday reach financial freedom.

How early you reach financial freedom depends on how aggressive you save.  Saving 50% of your income can result in achieving financial freedom in as little as 16 years.

Imagine an equal two-income household where you can live on one income and save the other.  Starting at age 24, that couple could potentially reach financial freedom by the age of 40.  All without sacrificing too much in terms of lifestyle.

Many people have done this, heck our family is doing it.  I’m closing in on 40 next year (imagine, I started this blog @ age 27) and by that point, most of our recurring expenses will be covered by our long-term dividend portfolio (woot!).

Investing with your eye on the horizon (ie. long term) is an extremely important discipline.  Why?  Because it lets the magic of compounding do the heavy lifting.  The more time that compounding is allowed to brew, the greater the impact on your wealth.

Power of Compound Interest

What is compound interest (returns)?  It’s when you keep your investment returns invested (not withdrawn), and you let not only your original capital grow but also the previously accumulated returns.

For example, say you put $10,000 into a TFSA and your portfolio returned 10% last year, so now you have $11,000 in your TFSA.  So your TFSA gained $1,000. Dandy. Say that a year passes, and your portfolio returned another 10%.  You didn’t just gain 10% on your original capital of $10,000, but also 10% on your returns, for a new portfolio value of $12,100.  Repeat for years going forward.

So as you can see, if you are properly invested over the long term, your returns will compound over the years.  The more years the returns are allowed to compound, the greater the effect.

Compounding can be represented as a math formula.  To keep things as simple as possible let’s assume that the compounding happens annually.

Portfolio Value = Principal * (1+ interest rate)^years

Pay particular attention to the exponential (years) of the interest rate.  That just shows that time is the fuel that keeps feeding the compounding beast.  Combine compounding with savings habits and now you are maximizing this force of nature.

Let’s use a realistic example of maximizing your TFSA annually.  To keep thing simple, let’s assume that the TFSA contribution limit is permanently set to $5,500, and you use a passive index investing strategy that averages a long-term return of 7%.

Years Savings Market Returns Portfolio Value
10 $55,000.00 $20,990.46 $75,990.46
15 $82,500.00 $55,709.62 $138,209.62
20 $110,000.00 $115,475.21 $225,475.21
25 $137,500.00 $210,369.71 $347,869.71
30 $165,000.00 $354,534.32 $519,534.32
35 $192,500.00 $567,802.83 $760,302.83
40 $220,000.00 $877,993.12 $1,097,993.12
45 $247,500.00 $1,324,121.21 $1,571,621.21
50 $275,000.00 $1,960,909.11 $2,235,909.11
55 $302,500.00 $2,865,107.26 $3,167,607.26
60 $330,000.00 $4,144,362.11 $4,474,662.11


The table and chart show that by year 20, the market returns start to overtake the total contribution amounts.  By year 30, market returns are double contributions.  By year 40, market returns are 4x contributions.  By year 50, market returns are 7x contributions and year 60, 12x contributions. Compounding really takes off with an exponential curve that will look like a vertical slope if you give it enough time.

The greater your market return, the greater the power of compound interest.  If you manage to increase your return by a percentage point (think lowering your MER), your compound interest works harder and will show significant results after 20-30 years.  See this post for more details.

Real Life Examples of Compound Interest

Warren Buffett, perhaps the greatest long-term investor of our time, became a millionaire in his 30’s.  However, he didn’t reach billionaire status until he was 56.  He continued to let his returns compound, and now at age 87 (about 30 years since his first billion), his net worth has grown to $84.1 billion.

As a personal example, I have been saving and investing for a couple of decades (since I was a teenager).  Compounding combined with our savings habits has resulted in a portfolio worth over $1M that pays out a healthy dividend.  The portfolio is to the point where annual gains are greater than our contributions.  With compounding @ 7%, it’s nice to imagine that our portfolio could be worth $5.5M in 25 years without any further contributions, but the reality is that we’ll be living off our portfolio much before then.

Final Thoughts

To close things off, this is just another article advocating long-term investing due to the power of compound interest.  When I say long-term, greater than 20 years is ideal because that is when compounding really starts to take over.  The more you save and contribute to your portfolio in the early days, the longer you’ll give compounding to do its work, which means the wealthier your future self will be.

What are you waiting for?

Here is some further reading on long-term investing:

  1. 5 philosophies of long-term investing success
  2. 6 ways to index your portfolio
  3. How to build a dividend portfolio
  4. Choosing a discount brokerage
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