How to use this calculator
Enter your net self-employment income (total revenue minus business expenses, which is your Schedule C net profit). Select your filing status and optionally enter any W-2 income from other employment that uses up part of the Social Security wage base.
The calculator shows your total SE tax, quarterly estimated payment amounts, and the deductible half that reduces your adjusted gross income on your tax return.
Understanding self-employment tax
When you work as an employee, your employer pays half of your Social Security and Medicare taxes (7.65%) and you pay the other half. As a self-employed individual, you pay both halves for a total of 15.3%.
The IRS applies SE tax to 92.35% of your net income (not the full amount) to account for the employer-equivalent deduction. Then you can deduct half of the resulting SE tax from your adjusted gross income, which reduces your income tax.
The Social Security portion (12.4%) has a wage base cap. Once your combined W-2 wages and SE income reach $176,100 in 2025, you stop paying the Social Security portion. Medicare (2.9%) has no cap, and an additional 0.9% applies to high earners.
Frequently asked questions
What is self-employment tax and how is it calculated?
Self-employment tax is 15.3% (12.4% Social Security + 2.9% Medicare) on 92.35% of your net SE income. For $100,000 in net income, the taxable base is $92,350 and SE tax is approximately $14,130.
Can I deduct self-employment tax?
Yes. You can deduct half of your SE tax as an adjustment to income on Form 1040. This is an above-the-line deduction available whether you itemize or take the standard deduction.
When are estimated quarterly payments due?
Quarterly payments are due April 15, June 15, September 15, and January 15 of the following year. If you expect to owe $1,000 or more, you should make these payments to avoid IRS penalties.
How do I reduce self-employment tax?
Deduct all legitimate business expenses, contribute to retirement accounts (SEP-IRA, Solo 401k), consider S-Corp election for income above $50,000-$60,000, and hire family members for legitimate work.
What is the Social Security cap for SE tax?
The 2025 Social Security wage base is $176,100. The 12.4% portion only applies up to this cap (on the 92.35% base). The 2.9% Medicare portion has no cap.