The Rule of 72: Why Time Builds Wealth

Most pharmacists should have the opportunity to become multimillionaires over the course of their careers. Not because they picked the right stocks or followed a complex investment strategy, but because of a simple concept rooted in math and time.

It’s called the Rule of 72. The Rule of 72 is a quick way to estimate how long it takes your money to double. Divide 72 by your expected annual rate of return, and you get the number of years it takes to double your investment.

For example, at a 7% annual return, your money doubles about every 10 years. And this is where things get interesting. At that same 7% return, $1 million at age 50 could grow to approximately $2 million by age 60 and $4 million by age 70, assuming it remains invested.

That kind of growth is driven by time, and that is the real lesson behind the Rule of 72: Time is the most powerful variable in building wealth. The earlier you begin saving and investing, the sooner compounding starts to work. Once it does, it begins stacking, each doubling on top of the next.

This is why 2 pharmacists earning similar incomes can end up in very different financial positions. The difference is often not income, but when they started and how consistently they stayed invested.

Of course, real life rarely follows a smooth, predictable path. Markets do not deliver a steady 7% return each year. They move up and down, sometimes sharply, over short periods.

Your personal situation evolves as well. Your comfort with risk and your ability to take risk will change over time, often leading to adjustments in how your portfolio is invested and the returns you might reasonably expect.

These factors matter and should be reflected in a thoughtful financial plan. But trying to perfect every assumption can distract from getting started and staying consistent.

In my conversations with pharmacists across all career stages, I often hear understandable concerns about being able to save and invest in a way that can build wealth: What about student loan debts? What about rising housing costs? What about childcare expenses?

These are real and important considerations. But they can also become reasons to delay getting started.

The challenge is that even a few years of delay can significantly reduce the long-term impact of compounding. Time lost is difficult to recover.

Once someone gets started, the focus often shifts to more technical questions: Where should I invest? Should I prioritize Roth or traditional accounts? Do I have the right asset allocation? Again, these are important questions that deserve thoughtful answers. But they are rarely the primary barrier.

The math is relatively simple, but the behavior is what makes it difficult. Building wealth requires consistency, staying the course during market volatility, and patience over decades. This is where many struggle because the process can feel slow and uneventful.

In fact, successful wealth building is often quite boring. There are no shortcuts that replace time and discipline. Progress can feel underwhelming in the early years, but over time, it becomes undeniable.

The Rule of 72 reminds us that building wealth is typically the result of many small, consistent decisions compounded over time.

Do you have a question or topic you would like to see addressed in a future column? Send Tim an email at [email protected]

Disclaimer: The information in this article is provided to you for your informational purposes only and is not intended to provide, and should not be relied on for, investment or any other advice. Read our full disclaimer: https://yfpwealth.com/disclaimer/.

About the Author

Timothy Ulbrich, PharmD, is a cofounder and CEO of YFP Wealth. Founded in 2015, YFP Wealth (formerly Your Financial Pharmacist) is on a mission to help pharmacists achieve financial freedom through fee-only, comprehensive financial planning services. Learn more at yfpwealth.com.