Who this is for
Dividing salary by 2,080 gives the textbook hourly equivalent, and the textbook number misleads in both directions. A salaried role that quietly expects 48-hour weeks pays a much lower true hourly rate than the division suggests, while an hourly role with overtime eligibility can out-earn its salaried equivalent at the same nominal rate.
Use the conversion both ways with honest hours, then run the resulting annual figure through the withholding estimate to compare per-paycheck take-home. The notes below cover the freelancer version of the conversion too, where overhead and unbillable time push the required rate far above the employee equivalent.