How Self-Employment Tax Is Calculated
Self-employment tax is the way freelancers and independent contractors pay into Social Security and Medicare — the same programs funded by FICA taxes on W-2 employees. The total SE tax rate is 15.3%, which breaks down into 12.4% for Social Security and 2.9% for Medicare.
Before applying that rate, the IRS lets you reduce your net self-employment income by 7.65% — multiplying it by 0.9235. This simulates the "employer half" deduction that W-2 workers get automatically. So on $75,000 of net SE income, you'd calculate SE tax on $69,263 (75,000 × 0.9235), not the full amount.
The Social Security portion has a wage base cap of $176,100 for 2025. Once your earnings hit that limit, you stop paying the 12.4% Social Security tax on additional income. Medicare has no cap — you pay 2.9% on all SE income regardless of how much you earn. If your combined earned income exceeds $200,000, an additional 0.9% Medicare surtax kicks in on the amount above that threshold.
What Is the Self-Employment Tax Rate for 2025?
The self-employment tax rate is 15.3% on your net earnings up to $176,100. Above that amount, only the 2.9% Medicare portion applies because Social Security is capped. If your combined earned income exceeds $200,000 ($250,000 for married filing jointly), you owe an additional 0.9% Medicare surtax.
Why 15.3%? Regular W-2 employees pay 7.65% of their wages toward FICA taxes, and their employer matches that with another 7.65%. When you're self-employed, you are both the employee and the employer — so you pay both halves: 7.65% + 7.65% = 15.3%. The IRS partially compensates for this by letting you deduct half of the SE tax from your income tax return.
The SE Tax Deduction – How to Save on Income Tax
The IRS allows you to deduct 50% of your self-employment tax when calculating your adjusted gross income (AGI). You claim this deduction on Schedule 1, Line 15 of your federal return — you don't need to itemize to take it.
This deduction reduces your federal income tax, but it does not reduce your self-employment tax itself. For example, if your total SE tax is $10,597, you can deduct $5,299 from your gross income. If you're in the 22% tax bracket, that saves you about $1,166 in income tax. The calculator above shows this deduction automatically so you can factor it into your overall tax planning.
When Do You Owe Self-Employment Tax?
You owe self-employment tax if your net self-employment income is $400 or more per year. This applies to freelancers, 1099 independent contractors, sole proprietors, and single-member LLCs taxed as sole proprietorships. Even part-time side income counts — if you earn $400+ from a side hustle on top of your W-2 job, you owe SE tax on that side income.
There's no exemption for small amounts above the threshold. If you earn $401 in net self-employment income, you owe SE tax on the full $401. The $400 threshold is a cliff, not a deduction.
How to Reduce Self-Employment Tax
The most direct way to lower your SE tax is to reduce your net self-employment income by deducting every legitimate business expense. Common deductions include:
- Business expenses: Software, equipment, supplies, marketing, and professional development all reduce your net SE income.
- Home office deduction: Deduct a portion of rent, utilities, and insurance if you use part of your home exclusively for business.
- S-Corp election: If you earn $60,000+ consistently, electing S-Corp status lets you split income into salary (subject to SE tax) and distributions (not subject to SE tax).
- Retirement contributions: SEP-IRA and Solo 401(k) contributions reduce your income tax, though not your SE tax directly.
- Vehicle and mileage: Business-related driving at 70 cents per mile (2025 rate) reduces your net SE income.
Frequently Asked Questions
Is self-employment tax the same as income tax?
No — self-employment tax is a separate tax that funds Social Security and Medicare. You pay it in addition to federal income tax. SE tax is 15.3% on net earnings, while income tax depends on your bracket and filing status. Both are owed on your self-employment income.
Do I owe SE tax if I lost money?
No. Self-employment tax is only owed on net profit. If your business expenses exceed your income, your net self-employment income is zero (or negative), and no SE tax is due. You may still be able to deduct the business loss against other income on your tax return.
What if I have both W-2 and 1099 income?
Your W-2 wages count toward the Social Security wage base ($176,100 in 2025). If your W-2 wages already exceed that cap, you won't owe the 12.4% Social Security portion on your SE income — only the 2.9% Medicare tax. Use the "Other Earned Income" field in this calculator to account for W-2 wages.
Can I deduct SE tax?
You can deduct half of your self-employment tax from your gross income on your federal return (Schedule 1, Line 15). This reduces your income tax but does not reduce your SE tax itself. It's an "above the line" deduction, meaning you get it whether you itemize or take the standard deduction.
Does an LLC pay self-employment tax?
A single-member LLC taxed as a sole proprietorship pays SE tax on all net profits — it's treated the same as a sole proprietor for tax purposes. However, an LLC that elects S-Corp taxation only pays SE tax on the owner's W-2 salary, not on distributions. This is why some freelancers earning $60,000+ consider the S-Corp election to reduce SE tax.