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.

Ira Heuvelman-Dobrolyubova | Getty Images