1. The Self-Employment FICA Multiplier
W-2 employees only see half of FICA withheld from their paystub (6.2% Social Security up to $184,500 and 1.45% Medicare). The hospital quietly pays the other 7.65% behind the scenes. On 1099, you must pay both halves via IRS Schedule SE. On a $400,000 contractor income, this extra payroll tax alone amounts to over $13,000/year.