Self Employment Tax Calculator

What Is Self-Employment Tax?

Self-employment tax is the Social Security and Medicare tax that self-employed individuals pay on their net business earnings. Employees split FICA taxes with their employer (each paying 7.65%), but self-employed people pay both halves: 12.4% for Social Security (on earnings up to $168,600 in 2024) plus 2.9% for Medicare (on all earnings), totaling 15.3%. Enter your net self-employment income, filing status, and any W-2 income in the calculator above to see the exact SE tax amount and the deductible portion.

How Is Self-Employment Tax Calculated Step by Step?

First, multiply net self-employment income by 92.35% (this adjustment accounts for the employer-equivalent portion of SE tax). On $80,000 net SE income: $80,000 x 0.9235 = $73,880 (SE tax base). Social Security portion: $73,880 x 12.4% = $9,161. Medicare portion: $73,880 x 2.9% = $2,142. Total SE tax: $11,303. Additionally, you can deduct half the SE tax ($5,652) from adjusted gross income, reducing your income tax. This deduction mirrors the fact that employers deduct their FICA contribution as a business expense, putting self-employed workers on roughly equal footing with employees.

Additional Medicare Tax for High Earners

Self-employed individuals earning above $200,000 (single) or $250,000 (married filing jointly) from all sources owe an additional 0.9% Medicare surtax on the excess amount. Combined with the standard 2.9% SE Medicare tax, the total Medicare rate becomes 3.8% on income above the threshold. A self-employed person earning $300,000: standard SE Medicare on the full amount = $8,700. Additional Medicare tax on $100,000 above threshold = $900. Total Medicare portion: $9,600. This surtax also applies to high-earning employees through W-2 withholding, so it is not exclusive to the self-employed.

SE Tax When You Also Have W-2 Employment

The Social Security wage cap ($168,600) applies to combined W-2 and SE income. If your W-2 job pays $130,000 (with Social Security already withheld by the employer), only $38,600 of SE income is subject to the 12.4% Social Security portion ($38,600 x 12.4% = $4,787). The 2.9% Medicare applies to all SE income regardless of W-2 earnings. This W-2 offset significantly reduces SE tax for people with side businesses supplementing a full-time job. A side business earning $30,000 when your W-2 salary already exceeds $168,600 owes zero Social Security SE tax - only the 2.9% Medicare ($870).

Quarterly Estimated Tax Payments

Self-employed individuals must pay estimated taxes quarterly (April 15, June 15, September 15, January 15) to avoid underpayment penalties. Each quarterly payment covers both income tax and self-employment tax. The safe harbor rule: pay at least 100% of last year total tax liability (110% if AGI exceeded $150,000) spread across four equal payments, or 90% of the current year liability. New freelancers with no prior-year reference should estimate current-year income and pay 25% of the expected total tax each quarter. IRS Form 1040-ES includes worksheets for calculating quarterly amounts.

Reducing Self-Employment Tax Legally

Maximize business expense deductions (home office, vehicle, equipment, insurance, professional development) to lower net SE income. S-Corp election: once self-employment income exceeds approximately $40,000-$50,000, operating as an S-Corporation allows you to pay yourself a "reasonable salary" (subject to FICA) and take remaining profits as distributions (not subject to SE tax). A sole proprietor earning $120,000 pays SE tax on the full amount ($17,000+). The same person as an S-Corp paying themselves a $70,000 salary pays FICA only on $70,000 ($10,710) while taking $50,000 as a distribution with no SE tax, saving approximately $6,300 per year.

Record Keeping for Self-Employment Income

Maintain separate business bank accounts and credit cards. Track all income (1099-NEC forms from clients, direct payments, platform earnings). Document every business expense with receipts or digital records. Use accounting software (QuickBooks Self-Employed, FreshBooks, Wave) to categorize transactions throughout the year rather than reconstructing records at tax time. The IRS requires keeping records for at least 3 years from the filing date (6 years if income is underreported by more than 25%). Organized records protect against audits, ensure you claim all legitimate deductions, and prevent overpaying SE tax on income that is offset by valid business expenses.

Common Deductions That Lower SE Tax Base

Home office deduction: simplified method allows $5 per square foot up to 300 sq ft ($1,500 max). Regular method calculates actual expenses proportional to office square footage. Vehicle expenses: standard mileage rate ($0.67/mile in 2024) or actual expenses (gas, insurance, repairs, depreciation) prorated by business use percentage. Health insurance premiums for self-employed individuals are 100% deductible from income (not a business expense but an above-the-line deduction). Retirement plan contributions: Solo 401(k) allows up to $23,500 employee plus 25% of net SE income as employer contribution. Each of these deductions reduces the income subject to both SE tax and income tax simultaneously.

Frequently asked questions