All seven SelfEmployLab calculators run on one shared federal tax engine, in your browser, using the numbers you type in. This page walks through that engine step by step, lists the 2026 figures it uses, and says plainly what it leaves out. The results are estimates built on simplified versions of IRS rules, not a substitute for your actual return.
The 2026 figures
Every calculator reads its rates and thresholds from one table, so a new tax year changes them in one place.
| Figure (2026) | Value | Source |
|---|---|---|
| Tax brackets, standard deduction ($16,100 single, $32,200 married filing jointly, $24,150 head of household), QBI threshold ($201,750 single, $403,500 joint) | Rates 10%–37% | IRS Rev. Proc. 2025-32 |
| Social Security wage base | $184,500 | Social Security Administration |
| Self-employment tax rates and 92.35% factor | 12.4% + 2.9% | IRS Schedule SE |
| Additional Medicare Tax thresholds | 0.9% above $200,000 single, $250,000 joint, $125,000 separate | IRS Form 8959 |
| Simplified home office rate | $5 per sq ft, up to 300 sq ft | IRS Publication 587 |
| Estimated tax due dates | April 15, June 15, September 15, 2026; January 15, 2027 | IRS Form 1040-ES |
When the IRS publishes the next year’s inflation adjustments, we add that year alongside the current one, and a year switch (for example “2026 | 2027”) appears above each calculator. Each calculator page lists its own sources at the bottom.
Step 1: Self-employment tax
- Multiply net profit by 92.35% to get net earnings from self-employment. If those net earnings are under $400, no SE tax is due and the calculator returns zero.
- Social Security, 12.4%, applies to net earnings up to the $184,500 wage base. Any W-2 wages you enter use up part of that base first.
- Medicare, 2.9%, applies to all net earnings.
- Additional Medicare Tax, 0.9%, applies to net earnings above your filing status threshold, again reduced by any W-2 wages.
Half of the Social Security and Medicare portions (not the 0.9%) is the deduction for half of SE tax, which lowers income for the income tax step.
Step 2: Federal income tax
- Adjusted gross income = profit + W-2 wages − half of SE tax.
- Subtract the standard deduction for your filing status. The calculators always use the standard deduction.
- Subtract the qualified business income (QBI) deduction: 20% of the smaller of your QBI (profit minus half of SE tax) or your taxable income before QBI. Above the threshold, the deduction shrinks in a straight line to zero over the next $75,000 ($150,000 joint). This is a simplification: it matches the rule for specified service businesses, and is conservative for other businesses, which may keep more of the deduction under the W-2 wage and property limits.
- Apply the 2026 brackets to what’s left.
A worked example
A single freelancer with $85,000 of profit and no other income:
| Net earnings: $85,000 × 92.35% | $78,497.50 |
| Social Security: × 12.4% | $9,733.69 |
| Medicare: × 2.9% | $2,276.43 |
| Self-employment tax | $12,010 |
| AGI: $85,000 − $6,005 (half of SE tax) | $78,995 |
| Minus $16,100 standard deduction | $62,895 |
| QBI deduction: 20% × $62,895 | $12,579 |
| Taxable income | $50,316 |
| Income tax: 10% of $12,400 + 12% of $37,916 | $5,790 |
| Total federal tax | $17,800 |
That’s about $4,450 per quarter, and about 21% of profit to set aside.
What each calculator adds
Self-employment tax
Step 1 only, with the half-SE-tax deduction and a quarter of the total shown alongside.
Quarterly estimated tax
Total federal tax (Steps 1 and 2) minus the federal withholding you enter, split into four equal payments. The penalty-safe minimum is the smaller of 90% of this year’s estimated tax or 100% of last year’s total tax (110% if last year’s AGI was over $150,000, or $75,000 married filing separately), minus withholding, divided by four. Without last year’s figures, it uses 90% of this year.
Tax set-aside
The federal share is the extra income tax your freelance profit causes on top of any W-2 wages, divided by profit. The SE tax share is SE tax divided by profit. The state share is the rate you enter (capped at 20%), applied to all profit.
1099 vs. W-2
The W-2 side is salary minus income tax (standard deduction, no QBI) and the employee share of Social Security and Medicare. The 1099 side is contract pay minus your expenses, then Steps 1 and 2. The break-even figure is the contract pay at which the two take-home amounts match.
Freelance hourly rate
The calculator searches for the profit that leaves your target take-home after Steps 1 and 2, adds your expenses to get revenue, and divides by billable hours per week × (52 − weeks off). The day rate assumes 8 billable hours.
S corp vs. LLC
The LLC side is a sole proprietorship: all profit goes through Steps 1 and 2. The S corp side pays your salary (capped at profit) through payroll: the employer and employee halves of Social Security and Medicare, plus federal unemployment tax at 0.6% of the first $7,000. Profit left after salary, employer payroll tax and the running costs you enter flows through as K-1 income, which alone gets the QBI deduction. Whether your salary is “reasonable” is up to you; the calculator uses the figure you enter.
Home office
Simplified method: $5 × office square feet, up to 300. Regular method: office area ÷ home area × the yearly housing costs and utilities you enter. The larger result is shown.
What the calculators don’t include
- State and local taxes, except the state rate you enter in the set-aside calculator
- Tax credits of any kind, such as the child tax credit or earned income credit
- Itemized deductions, retirement contributions and the self-employed health insurance deduction
- Investment income, capital gains, the Net Investment Income Tax and the alternative minimum tax
- The QBI deduction’s W-2 wage and property limits
- The annualized income method for uneven income, and IRS penalty and interest amounts
- Home office depreciation and the gross income limit; state unemployment tax for S corps
Spotted something that doesn’t match the IRS rules? Email [email protected]. Read our Editorial Standards for how we source and update figures.