In most cases, a bachelor's degree is the minimum education required for an entry-level engineering position. However, some engineering students choose to pursue a higher-level degree in engineering, such as a master's or even a PhD. While not required to break into the field, a PhD in engineering can translate into higher pay and an opportunity to teach or direct independent research.

PhD in Engineering Salary

According to a salary survey conducted by the American Society of Mechanical Engineers and the American Society of Civil Engineers, the average annual salary of an engineer with a PhD in engineering was $122,127 as of 2012. Half of engineers holding a PhD in the discipline reported salaries ranging from $92,000 to $144,500 per year. The lowest-paid 10 percent made $72,000 or less annually, while the highest-paid 10 percent earned $180,000 or more.

PhD Salary by Experience

The expected salary of an engineer with a PhD varies considerably according to experience. As of 2012, those who held a PhD reported an average starting salary of $81,406 to ASME and ASCE. This jumped to an average of $94,218 for those with between five and nine years of experience, while those who had between 15 and 19 years of experience averaged $125,972 per year. Those who had 25 or more years of experience reported the highest average salary, $147,014 per year.

Pay With Other Degrees

The $122,127 averaged by those with a PhD in engineering is more than that earned by engineers with most other types of education. As of 2012, ASME and ASCE found that engineers with a bachelor's degree in the field earned an average of $96,452 per year, while those who held a master's in engineering reported an average annual salary of $106,051. However, those who held a master's in business administration (MBA) reported a high average salary of $126,681, while engineers with both a master's in engineering and an MBA earned even more, averaging $131,107 per year.

Other Factors Affecting Engineering Salaries

Of course, an engineer's level of education and experience are not the only factors that have an impact on her salary. For example, engineers working in the Pacific Southwest tended to earn the highest median income in the U.S., $108,403 per year. By comparison, the lowest median pay by geographical location, $85,929 per year, was reported in the Upper Mountain states. And, of course, engineers make far more in some branches of engineering than in others. As of 2012, the highest average salary was reported by those in ocean engineering, who averaged $169,795 per year. The lowest average pay rates were reported by health care facility engineers ($87,732) and agricultural engineers ($88,319).