MathBench

Self-Employment Tax Calculator

Enter your expected net profit and see your 2026 self-employment tax (Social Security and Medicare itemized) plus the half-SE-tax deduction and how much to set aside each quarter.

Educational estimates only. This calculator is for planning and education. It is not financial, tax, or investment advice, and results may differ from what a lender, broker, or the IRS calculates for your situation. Confirm important decisions with a qualified professional.

Result

—self-employment tax
—Social Security (12.4%)
—Medicare (2.9%)
—½ SE tax deduction
—SE + est. income tax
—quarterly set-aside

How this calculator works

Self-employment tax is both halves of Social Security and Medicare: the 15.3% that employees split with their employer, landing on one person. The calculator follows Schedule SE: it multiplies profit by 92.35% to get net earnings, applies 12.4% Social Security up to the 2026 wage base of $184,500 (minus any base your W-2 wages already consumed), adds 2.9% Medicare on everything, and then computes the half-SE-tax deduction and a rough income-tax layer so the quarterly set-aside covers the whole bill, not just the payroll part.

The set-aside number is the one to move to a separate savings account every quarter. It's a planning estimate: business deductions, retirement contributions, and the QBI deduction all lower the final bill, so if any apply to you, expect to owe less than this.

The formula

Net earnings   = profit × 92.35%
Social Security = 12.4% × min(net earnings, $184,500 − W-2 wages)
Medicare        = 2.9% × net earnings          (no cap)
SE tax          = Social Security + Medicare
½ SE deduction  = SE tax ÷ 2
Income tax est. = (profit − ½ SE deduction) × marginal rate
Quarterly       = (SE tax + income tax est.) ÷ 4

Structure per IRS Schedule SE. The $184,500 wage base is the SSA's announced 2026 figure (up from $176,100 in 2025; it adjusts each October with the national wage index). The Additional Medicare Tax of 0.9% above $200,000 single / $250,000 joint is flagged in the results but not modeled.

Worked example

Say you expect $80,000 of net freelance profit in 2026, no W-2 job, 22% marginal bracket:

  1. Net earnings: 80,000 × 0.9235 = $73,880
  2. Social Security: 73,880 × 12.4% = $9,161 (under the cap)
  3. Medicare: 73,880 × 2.9% = $2,143
  4. SE tax: $11,304, with a $5,652 deduction against income tax
  5. Income tax estimate: (80,000 − 5,652) × 22% = $16,357
  6. Set aside: (11,304 + 16,357) ÷ 4 ≈ $6,915 per quarter

Call it 35% of profit, moved to a tax account as the invoices are paid. The freelancers who treat that transfer as non-optional are the ones April doesn't surprise.

Assumptions & tips

  • Profit means after expenses. SE tax applies to Schedule C net profit: revenue minus business expenses. Every legitimate expense you track cuts both SE and income tax. Sloppy bookkeeping is a voluntary tax.
  • Automate the set-aside. Transfer the percentage the day clients pay, not the week taxes are due. A separate high-yield account earns interest on the government's money until each deadline.
  • Retirement contributions are the big lever. A solo 401k or SEP-IRA contribution deducts against income tax (though not SE tax), often the largest legal reduction available to a profitable freelancer.
  • Safe harbor beats estimating. Paying 100% of last year's total tax (110% at higher incomes) through the year generally avoids underpayment penalties regardless of what this year brings, a useful floor when income is lumpy.
  • Figures on this page are 2026's. The wage base changes every year. If you're reading this in a later year, verify the current base at ssa.gov, and treat all of this as planning math to bring to a tax professional, not a filing position.

Frequently asked questions

Why is only 92.35% of my profit subject to SE tax?

Employees don't pay payroll tax on their employer's share of payroll tax, so Schedule SE gives the self-employed the same courtesy: net earnings are profit times 92.35 percent (knocking off the 7.65 percent an employer would have contributed) before the 15.3 percent rate applies. It is a small break that comes straight from the form.

I also have a W-2 job. Do I still owe self-employment tax?

Yes on the Medicare part, maybe less on Social Security. Your W-2 wages use up the Social Security wage base first ($184,500 in 2026). Only the room left over gets the 12.4 percent on your self-employment earnings. Medicare's 2.9 percent has no cap and applies to every dollar regardless. Enter your expected W-2 wages and the calculator handles the interaction.

When are quarterly estimated taxes due?

For a calendar-year filer: April 15, June 15, September 15, and January 15 of the following year. Note the uneven spacing, with the second payment only two months after the first. Missing them triggers underpayment interest even if you pay in full at filing. The set-aside figure this calculator produces is sized for those four payments.

Does an S-corp reduce self-employment tax?

It can: S-corp owners pay payroll tax only on the salary they pay themselves, not on distributions above it, but the IRS requires that salary to be reasonable for the work performed, and the structure adds payroll filings, a corporate return, and costs. The break-even is commonly tens of thousands of dollars of profit. That analysis belongs with a CPA, armed with the numbers from this page.

Sources

  1. Schedule SE (Form 1040), Self-Employment Tax. Internal Revenue Service, 2025 revision. irs.govThe form this calculator follows line for line: line 4a is the 92.35% net-earnings step, and line 7 carries the Social Security maximum that W-2 wages consume first.
  2. Topic no. 554, Self-employment tax. Internal Revenue Service. irs.govThe 15.3% rate split into 12.4% Social Security and 2.9% uncapped Medicare, plus the deduction for the employer-equivalent half.
  3. Contribution and Benefit Base. Office of the Chief Actuary, U.S. Social Security Administration (2026 base announced October 2025). Source of the $184,500 wage base at which this page caps the 12.4% Social Security portion.
  4. Questions and answers for the Additional Medicare Tax. Internal Revenue Service. irs.govThe 0.9% surtax above $200,000 single and $250,000 joint that the results flag but do not model.
  5. Publication 334 (2025), Tax Guide for Small Business. Internal Revenue Service. irs.govEstablishes that self-employment tax runs on Schedule C net profit after business expenses: what the profit field asks for, and why the tips insist on expense tracking.
  6. Publication 505 (2026), Tax Withholding and Estimated Tax. Internal Revenue Service. irs.govThe April, June, September and January estimated-payment dates the quarterly set-aside is sized for, and the 100% / 110% prior-year safe harbor in the tips.
  7. S corporation compensation and medical insurance issues. Internal Revenue Service. irs.govThe reasonable-compensation requirement behind the FAQ answer on whether an S-corp election lowers self-employment tax.

  • Tithing Calculator

    A tithe per paycheck and per year, on gross or take-home pay, plus what it costs you after tax.

  • Mortgage Calculator

    Full monthly payment (principal & interest plus taxes, insurance, PMI, and HOA) with a breakdown chart, amortization schedule, and payoff date.

  • Mortgage Payoff Calculator

    See how extra monthly or one-time payments change your payoff date and total interest, with a chart.

  • Biweekly Mortgage Calculator

    Compare a standard monthly schedule against biweekly half-payments: time and interest saved.