Self Employment Tax Calculator

The Self-Employment Tax Calculator estimates your US self-employment tax on net business profit, the deduction for half of that tax, a simplified Section 199A qualified business income (QBI) deduction, and a combined estimate with federal income tax at a rate you choose.

How It Works

1. Enter net earnings from self-employment. This is business profit after expenses, the Schedule C bottom line that self-employment tax is based on.
2. Add other income if relevant. Wages or other income can be included so the combined estimate reflects more of your return.
3. Choose filing status and business type. Single or married filing jointly changes the QBI phase-out thresholds the calculator applies, and the SSTB flag marks a specified service trade or business, which loses the QBI deduction at higher incomes.
4. Set your estimated income tax rate. The default is 22%. The calculator applies it to taxable income after the self-employment deduction and QBI deduction to produce the combined total and effective rate.

Formula

Self-employment tax is charged on 92.35% of net earnings, following Schedule SE:

$\text{Taxable earnings} = \text{Net earnings} \times 0.9235$

$\text{Social Security tax} = 12.4\% \times \min(\text{Taxable earnings}, \text{USD } 176{,}100)$

$\text{Medicare tax} = 2.9\% \times \text{Taxable earnings}$

$\text{SE tax} = \text{Social Security tax} + \text{Medicare tax}$

Half of the SE tax is then deductible, and the simplified QBI deduction is 20% of net earnings, phased out over income bands that depend on filing status and SSTB status:

$\text{Taxable income} = \max(0, \text{Net earnings} - 0.5 \times \text{SE tax} - \text{QBI} + \text{Other income})$

$\text{Combined tax} = \text{SE tax} + (\text{Taxable income} \times \text{Estimated income tax rate})$

Input Parameters

| Input | Unit | Realistic range | Notes | | --- | --- | --- | --- | | Net earnings | USD per year | USD 400 to USD 500,000 | Profit after business expenses | | Other income | USD per year | USD 0 and up | Optional; defaults to zero | | Filing status | Choice | Single or married filing jointly | Sets QBI phase-out bands | | SSTB flag | Yes or no | Service businesses only | Specified service trade or business | | Estimated income tax rate | Percent | 10% to 37% typical | Defaults to 22% |

Worked Example

A single filer with USD 100,000 of net self-employment profit, no other income, not an SSTB, using the default 22% income tax rate:

1. Taxable earnings: USD 100,000 x 0.9235 = USD 92,350.00.
2. Social Security tax: USD 92,350 x 12.4% = USD 11,451.40 (below the wage base, so no cap applies).
3. Medicare tax: USD 92,350 x 2.9% = USD 2,678.15.
4. Total SE tax: USD 11,451.40 + USD 2,678.15 = USD 14,129.55.
5. Deductible half: USD 7,064.78.
6. QBI deduction at 20% of net earnings: USD 20,000.
7. Taxable income: USD 100,000 - USD 7,064.78 - USD 20,000 = about USD 72,935. Estimated income tax at 22%: about USD 16,046.
8. Combined total: about USD 30,175, an effective rate of about 30.2% of net profit.

For contrast, at USD 250,000 of profit the Social Security portion caps out: taxable earnings are USD 230,875, but Social Security tax stops at USD 176,100 x 12.4% = USD 21,836.40, while Medicare continues on the full amount.

Interpreting Your Results

New freelancers are usually surprised by the combined figure, and the example shows why: on USD 100,000 of profit, almost half the estimated bill is self-employment tax, not income tax. The 15.3% combined SE rate replaces the employee-plus-employer payroll tax that a salary splits with an employer, so being your own employer means paying both halves, softened by the deduction for one half of it.

The effective rate near 30% in the example is a planning number for quarterly estimates, not a filing figure. Setting aside roughly that share of each payment received is the habit this estimate is meant to support. The QBI deduction is the most fragile part of the estimate, because real Section 199A eligibility depends on taxable income thresholds, wage and property tests, and business type; if your income is anywhere near the phase-out bands, treat the QBI amount as provisional.

Choosing the Right Tool

• Use this Self-Employment Tax Calculator for US sole proprietors and single-member LLCs estimating payroll-style tax on business profit, with a simplified QBI allowance.
• Use the Freelance Hourly Rate Calculator to work backwards from a take-home target to the rate you must bill, using the effective rate you found here as its tax input.
• Use the Capital Gains Tax Calculator when the income comes from selling assets rather than from a business.
• Use the Bonus Tax Calculator for supplemental wages paid through an employer, which follow withholding rules instead of Schedule SE.

Limitations

This is an estimator with deliberate simplifications. Its QBI phase-out applies the 2025 Section 199A income thresholds to a simplified income figure and does not reproduce the full rules, including the W-2 wage and qualified property limits, so high earners should not rely on its QBI figure. It applies one flat income tax rate instead of progressive brackets, ignores the standard deduction and most credits, excludes the Additional Medicare Tax on high earners, and does not model state or local tax. It also omits the rule reducing Social Security tax when you also have W-2 wages in the same year. It does not prepare Schedule SE or any part of a return.

Questions

Why is tax charged on only 92.35% of my profit?

The IRS excludes 7.65% of net earnings before applying the 15.3% rate, mirroring the employer share of payroll tax that employees never see in their wages. The adjustment is built into Schedule SE and this calculator applies it the same way.

Does this include my income tax as well as SE tax?

Yes, if you leave the estimated income tax rate set. The income tax portion is a flat-rate estimate on income after the half-SE-tax deduction and the simplified QBI deduction. Set the rate to zero if you want the self-employment tax on its own.

How much should I set aside for quarterly estimated payments?

The combined effective rate in your result is a reasonable starting point; in the worked example it is about 30% of net profit. Many self-employed people reserve 25% to 30% of each payment and reconcile at filing time. Your actual obligation depends on total household income, deductions, and state tax.

Sources and Methodology

The calculation follows IRS mechanics: the 92.35% net earnings adjustment and 15.3% combined rate from Schedule SE (Form 1040), the deduction for one-half of self-employment tax, and the Section 199A qualified business income deduction, all as described in IRS guidance for self-employed individuals. The Social Security wage base used is USD 176,100, the SSA limit for 2025; check the IRS and Social Security Administration for the current year's figure, and confirm QBI treatment with a tax professional because the calculator's phase-out bands are simplified.