The site reviewed eight factors that impact professional happiness, such as work-life balance, an employee's relationship with his or her boss and co-workers, office environment, job resources, compensation, opportunities for professional development and company culture.

CareerBliss' 50 Happiest Companies in America for 2015 was based on thousands of employees' independent company reviews reported to the site between 2013 and 2014.

Chevron Australia says on its careers page that working at the company is "not just a job. It's an extraordinary opportunity to help shape the future of energy".

"When you join Chevron, you'll find a workplace committed to your professional development," Chevron says.

"In addition to a competitive salary, you'll receive the support and tools needed to create your own career path - and we have a dedicated committee of professionals whose role is to help manage your career and set goals for your professional development.

"Chevron puts people at the centre of everything we do - from protecting the safety and health of our people and the environment, to helping you succeed. No matter where you are on your career path, Chevron offers continued education and training to help you cultivate your skills and expand your career within a truly global and collaborative workplace."

CareerBliss CEO Heidi Golledge said each year it evaluated the factors that impacted happiness, such as growth opportunity and company culture; it was also important to understand what type of industries were creating happier work environments overall.

"This year, we saw a surge of STEM-related (science, technology, engineering and maths) companies rank in the top 10," she said.

Thus medical device, pharmaceutical and consumer packaged goods company Johnson & Johnson topped the list, boasting an average annual salary of $70,000 a year, with 1500 job openings listed on CareerBliss.

California-based semiconductor company Broadcom was second, offering a higher average salary of $85,000.