Here's exactly how long it will take you to become a millionaire

Are you on track to become a millionaire?

If you're putting away $415 a month starting in your 20s, $651 a month starting in your 30s or $1,300 starting in your 40s, with a six percent return on investment, you're on the path to hitting that milestone by 67 .

But how soon could you become a millionaire if you're able to save more per month? CNN Money's helpful millionaire calculator can give you an idea of how close you are.

Let's assume zero savings and a six percent annual rate of return.

If you start saving $50 a month, it would take 77 years to become a millionaire by July of 2094.

But if you can start putting away $500 per month, you'll be a millionaire in 40 years, by June 2057.

If you're able to sock away $1,000 a month starting today, you'll reach millionaire status in just 30 years, by May 2047.

Try out the calculator yourself here.

These differences speak to the power of compound interest , in which any interest earned accrues interest on itself, and a little money invested now can amount to more than a lot of money invested later. In short: If you want to become a millionaire, the earlier you start investing, the better.

Of course, this calculation doesn't account for the many variables that can affect your wealth over several decades, including windfalls, emergencies and rises or dips in the market. But it can give you a good estimation of whether or not you're saving enough to retire comfortably.

Ready to put your money to work? The simplest starting point is to invest in your employer's 401(k) plan , a tax-advantaged retirement savings account. Next, consider alternate retirement savings accounts, such as a Roth IRA , traditional IRA and/or a health savings account .

You can also research low-cost index funds , which Warren Buffett recommends , and online investment platforms known as robo-advisers.

Don't miss: If you want to be a millionaire, start thinking like one