How do I actually calculate the return on investment of a college degree?

Think of a degree as an investment with costs and payoffs. Add up the total cost: tuition, fees, and living expenses not covered by aid, plus the interest on any loans, plus the opportunity cost of wages you give up while studying. Then estimate the lifetime earnings premium, the difference between what you'd likely earn with the degree versus without it. The Bureau of Labor Statistics and the Federal Reserve consistently find bachelor's degree holders earn substantially more over a career and have lower unemployment than those with only a high school diploma, but the size of that premium varies enormously by field. A degree that costs $120,000 and leads to a $45,000 job has a very different ROI than one costing $40,000 leading to $70,000. Run the numbers on your specific school-and-major combination, not averages.