Self-Employment Tax Calculator

If you do locums, moonlighting, telehealth, consulting or any other 1099 work, you owe self-employment tax on top of income tax. It's essentially Social Security and Medicare, and you pay both the employee and employer shares. This calculator estimates the bill so it doesn't catch you by surprise.

What this calculator does

Enter your net self-employment profit (1099 income minus business expenses), any W-2 wages you also earn and your filing status. The calculator shows:

• your self-employment tax,
• that tax as a share of your profit,
• the deductible half, which lowers your income tax, and
• the amount per quarter, if you pay it through estimated payments.

The formula in plain English

Net earnings = net profit × 92.35%.

Social Security part = 12.4% × the smaller of net earnings and the room left under the $184,500 wage base after your W-2 wages.

Medicare part = 2.9% × all net earnings, plus an extra 0.9% on combined wages and self-employment income above $200,000 ($250,000 joint).

Self-employment tax = Social Security part + Medicare part.

Deductible half = half of the regular self-employment tax, which reduces your taxable income for income tax.

A worked example

Dr. Kim is a hospitalist who does $60,000 a year of 1099 telehealth work with no W-2 job.

• Net earnings: $60,000 × 92.35% = $55,410.
• Social Security: 12.4% × $55,410 = about $6,871.
• Medicare: 2.9% × $55,410 = about $1,607.
• Self-employment tax: about $8,478, or about 14.1% of profit.
• Deductible half: about $4,239.
• Per quarter: about $2,119.

If Dr. Kim also had a W-2 job paying $250,000, her W-2 wages would already be above the Social Security wage base. She'd pay only the Medicare parts on her 1099 income, about $2,100 instead of $8,478.

Why it matters at each career stage

If you're: Resident / fellow

Moonlighting income paid as 1099 includes self-employment tax. Because residents' W-2 wages are well below the wage base, the full 15.3% applies. Set aside about a quarter to a third of moonlighting pay for taxes.

If you're: Employed

If your W-2 salary is above $184,500, side income is taxed mostly at the Medicare rate for self-employment tax, but still at your top income tax bracket. Use the quarterly estimated tax calculator to avoid penalties.

If you're: Practice owner

Practice owners structured as sole proprietors or partnerships pay self-employment tax on business profit. An S corporation can lower it by paying part of profit as a reasonable salary and part as distributions. Talk with a CPA about whether that fits.

Planning for the bill

Self-employment tax is easy to forget because nothing is withheld from 1099 payments. A simple habit helps: move a fixed share of every 1099 payment into a separate savings account as soon as it arrives. For most clinicians, setting aside 30% to 40% of 1099 income covers both self-employment and income tax, depending on your bracket and state.

Keep a simple record of business expenses during the year, too. A spreadsheet or app that tracks receipts and mileage makes tax time faster and helps you claim every deduction you're entitled to.

Ways to lower the bill

Track business expenses. Licensing, malpractice, CME, equipment, a home office and mileage for work travel can all reduce profit.

Open a solo 401(k) or SEP IRA. Contributions lower income tax, though not self-employment tax.

Consider entity structure. S corporation status can save self-employment tax at higher profits, but adds payroll and accounting costs.

Pay quarterly. Paying on time avoids underpayment penalties.

Next, plan payments with the quarterly estimated tax calculator, compare W-2 vs 1099 offers, and read our guide to W-2 vs 1099 for clinicians.