Breaking Down Self-Employment Tax
Self-employment tax consists of two components: Social Security tax at 12.4% and Medicare tax at 2.9%, totaling 15.3% of your net self-employment income. Unlike W-2 employees who split this cost with their employer, self-employed individuals pay both halves. The 92.35% factor adjusts your net income to account for the deductible portion of SE tax.
The SE Tax Deduction
You can deduct 50% of your self-employment tax from your adjusted gross income, reducing your federal income tax liability. This deduction is taken above-the-line, meaning you benefit even if you don't itemize. For example, if you owe $8,000 in SE tax, you can deduct $4,000 from your taxable income.
W-2 and 1099 Income Interaction
If you have both W-2 employment and 1099 self-employment income, the Social Security tax you already paid through your employer counts toward the annual wage base limit. Any 1099 income below the cap is still subject to the full 15.3% SE tax. Use this calculator to plan quarterly estimated payments and avoid underpayment penalties.