Enter your net self-employment income to calculate your complete 2026 SE tax (Social Security, Medicare, and Additional Medicare Tax) on Schedule SE, plus your quarterly payment amount.
Self-Employment Tax Calculator
Live| Adjusted SE base (x92.35%) | $73,880.00 |
| Social Security portion (12.4%) | $9,161.12 |
| Medicare portion (2.9%) | $2,142.52 |
| Additional Medicare Tax (0.9%) | $0.00 |
| Total SE tax | $11,303.64 |
| Deductible half (above-the-line) | $5,651.82 |
| Quarterly estimated payment | $2,825.91 |
The formula
$80,000 net self-employment income, no W-2 wages, single filer: adjusted base $73,880, Social Security portion $9,161.12, Medicare portion $2,142.52, no Additional Medicare Tax (well under the $200,000 threshold) - total SE tax of $11,303.64, or about $2,825.91 per quarter.
Why quarterly payments matter for the self-employed
Unlike an employee, whose taxes are withheld automatically from every paycheck, a self-employed person generally must estimate and pay both SE tax and income tax four times a year - mid-April, mid-June, mid-September, and mid-January of the following year. Skipping this and paying everything at filing time can trigger an underpayment penalty, even if the full amount is eventually paid. A common safe harbor is paying at least 100% of last year's total tax liability (110% if your prior-year AGI was over $150,000) spread across the four due dates, which protects you from the penalty even if this year's income ends up higher than expected.
Step-by-step guide
- Find your net self-employment income - Schedule C net profit (or Schedule F for farming, or your share of partnership income).
- Enter any W-2 wages you also earned this year - these use up the Social Security wage base first, reducing the SE-taxable Social Security portion.
- Read your total SE tax and the deductible half - remember this is separate from, and in addition to, your regular federal income tax.
Why the 92.35% adjustment exists
This adjustment isn't arbitrary - it exists to put self-employed taxpayers on comparable footing with employees. A traditional employee's Social Security and Medicare taxes are calculated on their gross wages, but their employer's matching half of FICA is never counted as the employee's own income in the first place. Since a self-employed person is effectively both employee and employer, the 92.35% factor backs out the equivalent of that "employer share" from the tax base, so SE tax isn't calculated on money that a comparable employee's wages wouldn't have included either.
Common mistakes
Frequently asked questions
Do I owe SE tax on investment income like dividends or capital gains?
No - SE tax applies only to earned income from self-employment (business profits, freelance income, gig work). Passive income like capital gains, dividends, interest, and rental income is exempt from SE tax entirely.
Is there a minimum income before I owe SE tax?
Yes - you generally must file Schedule SE and pay SE tax once net self-employment earnings reach $400 or more for the year.
Does the Medicare portion of SE tax ever stop?
No - unlike the Social Security portion, the 2.9% Medicare tax has no income ceiling and applies to all of your adjusted SE base, however high your income goes. High earners additionally owe an extra 0.9% above $200,000 (single/HoH), $250,000 (MFJ), or $125,000 (MFS).
What's the "safe harbor" for avoiding an underpayment penalty?
Generally, paying at least 100% of last year's total tax liability (110% if your prior-year AGI exceeded $150,000), spread across the four quarterly due dates, protects you from an underpayment penalty even if your actual tax for the current year turns out higher.
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