When you're an employee, your pay stub shows FICA deductions: Social Security (6.2%) and Medicare (1.45%). What it doesn't show is that your employer pays an identical 6.2% + 1.45% on your behalf. You never see that money because it never hits your paycheck.
When you're self-employed, there's no employer. You pay both halves. That's 12.4% for Social Security plus 2.9% for Medicare, a total of 15.3%. This is self-employment tax, and it hits before your federal and state income taxes are even calculated.
It's the expense that surprises every new freelancer.
How It's Calculated
Self-employment tax is assessed on 92.35% of your net self-employment income (not your gross). That 7.65% reduction is meant to approximate the benefit that employees get from not paying tax on their employer's FICA contribution. So if you earned $80,000 in freelance income, your SE tax base is $73,880, and your self-employment tax is approximately $11,304.
The Deduction You Shouldn't Miss
You can deduct half of your self-employment tax from your adjusted gross income. Using the example above, you'd deduct about $5,652. This doesn't reduce your SE tax directly, but it lowers your income tax. At the 22% bracket, that's roughly $1,243 in income tax savings.
Use our 1099 vs W2 Calculator to see the full self-employment tax picture. The "Tax Burden Breakdown" tab shows exactly how SE tax, federal income tax, and state tax stack up.
Quarterly Estimated Payments
Unlike employees, the IRS doesn't wait until April to collect from you. You're expected to pay quarterly estimated taxes: in January, April, June, and September. If you underpay, you'll owe penalties. A safe harbor approach is to pay 100% of last year's total tax liability spread across four quarters (110% if your income was above $150,000).
Strategies That Actually Reduce Self-Employment Tax
First, deduct every legitimate business expense: home office, equipment, software, mileage, professional development. Every dollar of expenses reduces your net income, which directly reduces your SE tax base. Second, consider an S-Corp election once your net income consistently exceeds $50,000–$60,000. An S-Corp lets you split income between a "reasonable salary" (subject to FICA) and distributions (not subject to FICA), potentially saving thousands. Talk to a CPA before making this move. It has compliance costs.
Self-employment tax is the price of being your own boss. It's steep, but understanding it means you can plan for it, deduct against it, and stop being shocked when quarterly estimates come due.
For a deeper look at the SE tax calculation with examples, CalcTools has a full walkthrough.