Self-Employment Tax Calculator (SE Tax 2024–2025)

How self-employment tax works

When you work as an employee, your employer pays half of Social Security (6.2%) and Medicare (1.45%) taxes on your behalf. As a self-employed individual (freelancer, consultant, sole proprietor, or independent contractor), you are both employer and employee, so you pay the full 15.3% yourself. The IRS calls this the self-employment tax and it is computed on Schedule SE.

The 92.35% adjustment

Before applying the 15.3% rate, the IRS reduces your net self-employment income by 7.65% (to 92.35%). This mirrors how employees are only taxed on their take-home wage, not on the employer's matching contribution. The result is a slightly lower SE tax base than your gross net income.

The deductible half of SE tax

You can deduct 50% of your SE tax as an above-the-line deduction on Form 1040, reducing your Adjusted Gross Income. This deduction is available whether or not you itemize, and it meaningfully reduces your federal income tax bill.

Quarterly estimated payments

Self-employed individuals typically don't have taxes withheld from their pay, so the IRS requires quarterly estimated tax payments (Form 1040-ES) due around April 15, June 15, September 15, and January 15. Underpaying can trigger an underpayment penalty. A safe harbor is to pay at least 100% of last year's total tax (110% if AGI exceeded $150,000).

Ways to reduce your SE tax

• Deduct legitimate business expenses: every dollar of expense reduces net SE income dollar-for-dollar.
• Health insurance deduction: self-employed individuals can deduct 100% of health insurance premiums.
• Retirement contributions: SEP-IRA contributions (up to 25% of net SE income, max $70,000 in 2025) and Solo 401(k) contributions reduce both income tax and the SE tax base.
• S-Corp election: paying yourself a reasonable salary and taking remaining profits as distributions can reduce the portion subject to SE tax (consult a CPA).

2025 Social Security wage base

The Social Security portion of self-employment tax (12.4%) only applies to the first $176,100 of net self-employment earnings in 2025. Earnings above this cap are subject only to the 2.9% Medicare portion (no cap). This means the effective SE tax rate decreases as income rises above $176,100.

Additional Medicare Tax

Self-employed individuals with high income owe an additional 0.9% Medicare surtax on net self-employment income above $200,000 (Single) or $250,000 (Married Filing Jointly). This surtax is not deductible (unlike the regular SE tax deduction for the employer half). Many self-employed earners are unaware of this additional layer because it does not appear on Schedule SE - it is calculated on Form 8959 and flows to Form 1040.

Quarterly payment calendar

Safe harbor rule: to avoid an underpayment penalty, pay at least (a) 90% of your current-year tax liability, or (b) 100% of last year's total tax (110% if your prior-year AGI exceeded $150,000). Most self-employed individuals use the prior-year safe harbor to avoid recalculating each quarter.