Experts suggest consulting with online tools. The U.S. Department of Labor has an online database that can help you find the average wage for more than 800 jobs.
Next up, try to network and talk to people in similar jobs at different companies.
Finally, ask your manager once you have done your research. Experts suggest framing the conversation as a discussion to get the best results.
Try asking your manager how your current pay was determined, and what you need to do to land a promotion.