US Self-Employment Tax & Quarterly Estimated Tax Calculator
Schedule SE, half-SE deduction, income tax estimate and 1040-ES payments.
Tax year 2026 Schedule SE · Form 1040-ES · Official sources
Quarterly estimated tax (Form 1040-ES)
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A due date on a Saturday, Sunday or legal holiday moves to the next business day. You can skip the January payment if you file and pay everything by January 31.
Schedule SE, line by line
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Income tax estimate
Rules used and official sources
- IRS: Self-employment tax (Social Security and Medicare taxes)
- IRS Schedule SE (Form 1040), Self-Employment Tax
- IRS Topic no. 751, Social Security and Medicare withholding rates
- Social Security Administration, cost-of-living increase and other determinations (Federal Register)
- IRS Topic no. 560, Additional Medicare Tax
- IRS Publication 505, Tax Withholding and Estimated Tax (Worksheet 2-1)
- IRS Rev. Proc. 2025-32: tax rate schedules, standard deduction, health FSA limit
Tax rules and rates change. This calculator follows the rules described on this page and may not cover every situation. Check the official source or a qualified tax professional before filing or invoicing.
About the US Self-Employment Tax & Quarterly Estimated Tax Calculator
Freelancers, contractors and other self-employed people pay Social Security and Medicare through self-employment tax. Enter your net profit and any W-2 wages and see Schedule SE worked out line by line: net earnings at 92.35% of profit, 12.4% for Social Security up to the wage base, 2.9% for Medicare, Additional Medicare Tax above the threshold, and the deduction for half of the tax.
The calculator then estimates your federal income tax with the rate schedules and standard deduction, and splits what you still owe into the four quarterly Form 1040-ES payments, using the safe-harbor rule from IRS Publication 505: pay at least the smaller of 90% of this year’s tax or 100% of last year’s (110% if last year’s AGI was over $150,000). Nothing you enter leaves your browser.
How to use it
- Enter your net profit for the year — Schedule C line 31, or your self-employment income from a partnership — and your filing status.
- If you also have a job, enter your W-2 wages (box 5); they use up part of the Social Security wage base and the Additional Medicare threshold. Married couples filing jointly can add the spouse’s wages.
- Optionally add other income, deductions you take (self-employed health insurance, SEP or solo 401(k) contributions) and credits.
- Enter last year’s total tax and AGI from your return to use the prior-year safe harbor, and any tax withheld this year.
- Read your self-employment tax, the income tax estimate and the four payment amounts with their due dates; copy the summary for your records.
Examples
Net earnings $46,175.00 · Social Security $5,725.70 · Medicare $1,339.08 · self-employment tax $7,064.78 · half deductible $3,532.39
Only $34,500 of the wage base is left: Social Security part $4,278.00 + Medicare part $1,606.89 = $5,884.89
Self-employment tax $11,303.64 · income tax about $5,343.82 · four payments of about $3,745.68 (90% of this year’s tax)
How self-employment tax is worked out (Schedule SE)
The self-employment tax rate is 15.3%: 12.4% for Social Security and 2.9% for Medicare (IRS). Schedule SE applies it to net earnings from self-employment, which are your net profit × 92.35% (0.9235). If net earnings are under $400 there is no self-employment tax.
The 12.4% part applies only up to the Social Security wage base of $184,500 (IRS Topic 751), counting your W-2 Social Security wages first; the 2.9% part has no limit. You deduct half of the self-employment tax when working out your adjusted gross income, which lowers your income tax but not the self-employment tax itself.
Additional Medicare Tax
A further 0.9% applies to wages and self-employment income above $250,000 for married filing jointly, $125,000 for married filing separately and $200,000 for everyone else. For self-employment income the threshold is first reduced by your Medicare wages (IRS Topic 560). It is not part of the deductible half.
Quarterly estimated tax and the safe harbor
You generally avoid an underpayment penalty if your withholding and estimated payments cover the smaller of 90% of this year’s tax or 100% of last year’s tax — 110% if last year’s AGI was more than $150,000 ($75,000 married filing separately) — or if you will owe less than $1,000 with your return (Publication 505, Worksheet 2-1). Payments are due on the 15th of April, June and September and in January of the following year; a due date on a Saturday, Sunday or legal holiday moves to the next business day.
If you had no tax liability last year, were a U.S. citizen or resident alien for the whole year and that year covered 12 months, you do not have to pay estimated tax this year.
The income tax estimate
Income tax is estimated with the rate schedules and standard deduction for the tax year: $16,100 single or married filing separately, $32,200 married filing jointly, $24,150 head of household, plus $1,650 or $2,050 for each 65-or-older or blind box. Without itemizing you can add cash gifts to charity of up to $1,000 ($2,000 jointly), as Worksheet 2-1 allows.
The qualified business income deduction is simplified: 20% of qualified business income, limited to 20% of taxable income before the deduction and at least $400 with $1,000 or more of qualified business income. It is computed only below the threshold ($201,750, or $403,500 married filing jointly); above it, enter the figure from Form 8995-A.
Limitations
- Capital gains and qualified dividends are taxed here at ordinary rates; the alternative minimum tax, net investment income tax and refundable credits are not included.
- Only one self-employed person is modelled; if both spouses have self-employment income, each needs their own Schedule SE.
- The farm and nonfarm optional methods of Schedule SE, church employee income and the annualized income installment method are not covered.
- The qualified business income deduction is a simplified estimate below the threshold only.
- State income and self-employment-related taxes are not included.
Privacy
Everything happens in your browser. What you enter or open here is not uploaded or stored by MySmartCoPilot.
Frequently asked questions
How much should I set aside for taxes as a freelancer?
At least your self-employment tax (about 14.1% of profit: 15.3% × 92.35%) plus your income tax. Enter your numbers above: the total tax and the quarterly payment amounts show what to put aside.
Is self-employment tax the same as income tax?
No. Self-employment tax is the Social Security and Medicare tax that an employer and employee would split; income tax is separate and depends on your total taxable income. You pay both, and half of the self-employment tax is deductible for income tax.
I have a job and a side business. Do I pay Social Security twice?
Not above the wage base. Your W-2 Social Security wages count first, and the 12.4% part of self-employment tax applies only to the rest of the $184,500 wage base. The 2.9% Medicare part applies to all net earnings.
When are quarterly estimated taxes due?
Usually April 15, June 15, September 15 and January 15 of the following year; the calculator lists the exact dates for the tax year it computes. You can skip the January payment if you file and pay everything by January 31.
What if my income is uneven during the year?
Equal quarterly payments assume income spread evenly. If most of it arrives late in the year, the annualized income installment method (Form 2210, Schedule AI) can lower earlier payments; it is not calculated here.
Is anything I enter stored?
No. The calculation runs entirely in your browser.