A master's degree can be an intermediate step on the way to a doctoral degree, or it can be an appropriate degree for starting a professional career. In some fields, it is impossible to advance without earning a master's degree. While salaries of those who have earned master's degrees vary by field, the difference in lifetime earnings between those with a master's degree and those with a bachelor's degree is significant. On average, according to statistics from the U.S. Census Bureau, those with master's degrees earn $400,000 more than someone with a bachelor's degree over the course of an entire career - and $900,000 more than someone with an associate's degree. Those who earn master's degrees gain both professional skills and a competitive edge in their chosen field.