Self-Employment Tax Explained: The Complete 1099 Guide
If you are a freelancer, independent contractor, gig worker, or run your own business, you face a tax reality that employees never deal with: self-employment tax. On top of regular federal and state income tax, the self-employed must pay both the employee and employer portions of Social Security and Medicare taxes. This guide covers everything you need to know about SE tax, quarterly estimated payments, and the deductions that can reduce your bill.
Calculate your exact self-employment tax liability with our self-employment tax calculator.
What Is Self-Employment Tax?
Self-employment (SE) tax is the equivalent of FICA taxes that employees and employers split. When you are employed by a company, you pay 7.65% of your wages for Social Security (6.2%) and Medicare (1.45%), and your employer pays a matching 7.65%. When you are self-employed, you are both the employer and the employee, so you pay the full 15.3%.
| Component | Employee Rate | Employer Rate | SE Total |
|---|---|---|---|
| Social Security | 6.2% | 6.2% | 12.4% |
| Medicare | 1.45% | 1.45% | 2.9% |
| Total | 7.65% | 7.65% | 15.3% |
This is a significant additional tax burden. On $100,000 of self-employment income, the SE tax alone is approximately $14,130 (before the adjustments described below), on top of whatever federal and state income tax you owe.
How SE Tax Is Calculated
The calculation involves several steps that reduce the effective rate slightly below 15.3%:
Step 1: Calculate Net Self-Employment Income
Start with your gross self-employment revenue and subtract all ordinary and necessary business expenses. This is your net profit, reported on Schedule C (or Schedule K-1 for partnerships).
Step 2: Multiply by 92.35%
You only pay SE tax on 92.35% of your net self-employment income. This adjustment mirrors the fact that employees do not pay FICA on the employer's share of FICA. If your net income is $100,000, your SE tax base is $100,000 x 0.9235 = $92,350.
Step 3: Apply the Rates
- Social Security (12.4%) on the first $176,100 of the SE tax base in 2026
- Medicare (2.9%) on the entire SE tax base, with no cap
- Additional Medicare Tax (0.9%) on SE earnings above $200,000 (single) or $250,000 (married filing jointly)
Example: $100,000 in Self-Employment Income
| Step | Calculation | Amount |
|---|---|---|
| Net SE Income | - | $100,000 |
| SE Tax Base (92.35%) | $100,000 x 0.9235 | $92,350 |
| Social Security Tax | $92,350 x 12.4% | $11,451.40 |
| Medicare Tax | $92,350 x 2.9% | $2,678.15 |
| Total SE Tax | - | $14,129.55 |
The Deductible Half of SE Tax
Here is some good news: you can deduct half of your self-employment tax as an above-the-line deduction on your Form 1040. This reduces your adjusted gross income (AGI), which in turn reduces your income tax. In the example above, you would deduct $7,064.78 ($14,129.55 / 2) from your AGI. At a 22% marginal income tax rate, that saves an additional $1,554 in income tax.
This deduction is available whether you take the standard deduction or itemize. It only reduces income tax, not the SE tax itself.
Quarterly Estimated Tax Payments
Unlike employees who have taxes withheld from each paycheck, the self-employed must make quarterly estimated tax payments to avoid underpayment penalties. These payments cover both income tax and self-employment tax. The quarterly due dates for 2026 are:
| Quarter | Income Period | Due Date |
|---|---|---|
| Q1 | January 1 - March 31 | April 15, 2026 |
| Q2 | April 1 - May 31 | June 16, 2026 |
| Q3 | June 1 - August 31 | September 15, 2026 |
| Q4 | September 1 - December 31 | January 15, 2027 |
You can avoid the underpayment penalty by paying at least the lesser of: (1) 90% of your current year tax liability, or (2) 100% of your prior year tax liability (110% if your AGI was over $150,000). Most self-employed people use the prior-year safe harbor method because it is easier to calculate.
Schedule SE: Where SE Tax Is Reported
Self-employment tax is calculated on Schedule SE, which is attached to your Form 1040. If your net self-employment income is $400 or more, you must file Schedule SE. The form walks through the 92.35% calculation, applies the Social Security wage base cap, and computes your total SE tax. The result flows to Schedule 2, line 4, and then to your Form 1040.
The Qualified Business Income (QBI) Deduction
Section 199A of the tax code allows eligible self-employed individuals and pass-through business owners to deduct up to 20% of their qualified business income. This is a significant tax break that can substantially reduce your effective income tax rate.
- Available to sole proprietors, partnerships, S-corps, and certain trusts/estates
- The deduction is limited for specified service businesses (law, medicine, consulting, etc.) when taxable income exceeds $191,950 (single) or $383,900 (married filing jointly)
- The deduction reduces income tax but not self-employment tax
- W-2 wages and qualified property limitations may apply at higher income levels
For our $100,000 self-employment example, the QBI deduction could be as much as $20,000, saving $4,400 at the 22% marginal rate.
Key Business Deductions for the Self-Employed
Reducing your net self-employment income through legitimate business deductions lowers both your income tax and your SE tax. Common deductions include:
- Home office deduction: Simplified method ($5/sq ft, max 300 sq ft = $1,500) or actual expenses
- Vehicle expenses: Standard mileage rate (67 cents/mile for 2026) or actual expenses
- Health insurance premiums: 100% deductible for the self-employed (above-the-line deduction)
- Retirement contributions: SEP IRA (up to 25% of net SE income, max $70,000), Solo 401(k), or SIMPLE IRA
- Business equipment and software: Section 179 expensing or depreciation
- Professional services: Accountant, attorney, business insurance
- Education and training: Courses, conferences, and subscriptions related to your business
- Internet and phone: Business-use percentage of these expenses
S-Corp Election: Reducing SE Tax
One advanced strategy to reduce self-employment tax is electing S-corporation status. As an S-corp, you pay yourself a "reasonable salary" (subject to FICA) and take remaining profits as distributions (not subject to SE tax). For example, if your business earns $150,000 and you pay yourself an $80,000 salary, only $80,000 is subject to FICA, potentially saving thousands in SE tax.
However, S-corp status has additional costs (payroll processing, additional tax returns, state fees) and the IRS closely scrutinizes "reasonable salary" determinations. This strategy typically makes sense when net SE income consistently exceeds $60,000-$80,000.
SE Tax When You Have Both W-2 and 1099 Income
If you have a day job (W-2) and freelance on the side (1099), your W-2 wages count toward the Social Security wage base. If your W-2 wages are already at or above $176,100, you will not owe the 12.4% Social Security portion of SE tax on your freelance income. You will still owe the 2.9% Medicare portion on all SE income.
Additionally, if you are already having income tax withheld from your W-2 job, you can increase your W-4 withholding to cover the tax on your self-employment income instead of making quarterly estimated payments. See our W-4 guide for details.
Bottom Line
Self-employment tax is a significant cost, but understanding how it works allows you to plan effectively and take advantage of available deductions. The keys are: track and deduct all legitimate business expenses, make timely quarterly payments, claim the deductible half of SE tax, and consider the QBI deduction.
Run the numbers with our self-employment tax calculator, and see how your total tax compares to employee scenarios with our income tax calculator.