What this calculates

Three taxes stacked, the way the IRS actually structures them:

Self-Employment Tax (Schedule SE) — 15.3% on 92.35% of your net SE earnings. This is the FICA equivalent for self-employed people: 12.4% Social Security (capped at the wage base — $176,100 for 2025, $184,500 for 2026) plus 2.9% Medicare (uncapped). Half of this is deductible from AGI.
Federal Income Tax — IRS published 2025 + 2026 brackets, applied after the standard deduction (or itemized, whichever is higher).
State Income Tax — for the 8 most populous US states (covers ~50% of the population): California, Texas, New York, Florida, Pennsylvania, Illinois, Ohio, Georgia. Texas and Florida have no state income tax.

The order matters. SE tax is calculated first because half of it reduces your AGI for federal purposes. State tax is calculated on AGI (with state-specific deductions where applicable).

What you put in

Net SE income: your Schedule C bottom line. Gross receipts minus business expenses. NOT gross sales.
W-2 wages: if you have a day job alongside self-employment, this affects how much Social Security wage base remains. Above $184,500 combined (2026), no more SS portion is owed.
Filing status: Single, MFJ, or Head of Household. Brackets and standard deduction differ.
State: pick yours from the 8 modeled, or “Other” for federal-only.
Tax year: 2025 or 2026. Brackets and standard deduction shift slightly each year.
Other income: interest, dividends, rental income.
Itemized deductions: only enter if your itemized total exceeds the standard deduction.

What you get out

Total tax burden — the sum of SE tax, federal income tax, and state tax.
Take-home — gross income minus total tax.
Effective tax rate — total tax ÷ gross income. This is the number that matters for comparing self-employed vs W-2.
Marginal federal rate — the rate your next dollar of income would be taxed at.
Schedule SE breakdown — Social Security portion, Medicare portion, half-deduction.
Federal income tax breakdown — AGI, deduction used (standard vs itemized), taxable income, tax owed.
State income tax — applicable if your state taxes income.

How the math works (Schedule SE specifically)

If you’ve never filed self-employed before, this is the part that catches everyone out:

You don’t pay 15.3% on your full self-employment income. You pay it on 92.35% of your net SE earnings. The 7.65% reduction is to make the math equivalent to W-2 employees, who pay 7.65% FICA themselves and have an employer pay another 7.65% — the employer share is deductible from the employee’s wages, so to mirror that, the IRS lets self-employed people deduct an equivalent share before calculating SE tax.

Then half of the SE tax you calculated is deductible from your AGI for federal income tax purposes. So if you owe $7,000 in SE tax, you reduce your AGI by $3,500 before applying federal income tax brackets.

This deduction is automatic — the calculator handles it. But it’s worth understanding because it means your effective SE tax burden is less than the full 15.3% headline rate.

Frequently asked questions

faq: - q: “I have a W-2 job and side hustle. Do I owe SE tax on the side hustle?” a: “Yes — any net SE income above $400/year triggers SE tax. The Social Security portion is capped at the wage base ($184,500 for 2026); if your W-2 wages already used most of that, the SE tax SS portion is reduced. The calculator factors this in when you enter W-2 wages.” - q: “What’s the difference between SE tax and federal income tax?” a: “SE tax (Schedule SE) is FICA — Social Security + Medicare — the payroll tax. It funds those programs. Federal income tax is separate and applies to all income (W-2, SE, investment, etc.). You owe both. The calculator separates them out so you can see each.” - q: “Do I have to file Schedule SE if my SE income is small?” a: “Only if your net SE earnings are $400 or more in the year. Below $400, no SE tax owed (though you may still owe federal income tax).” - q: “Why isn’t my state listed?” a: “We model the 8 most populous states which cover ~50% of the US population. For other states, run the calculator with ‘Other’ selected — you’ll get accurate federal+SE numbers and can add state separately. Most states’ rates and brackets are similar to the ones modeled, so the federal+SE numbers will be the bulk of your obligation.” - q: “How accurate is this for tax planning?” a: “Numbers are calculated against IRS-published 2025 and 2026 federal brackets, FICA wage bases, and state DOR-published rates. Edge cases not modeled: AMT (Alternative Minimum Tax), QBI deduction (Section 199A — can reduce SE income by up to 20%), local/city income tax (e.g., NYC adds 3-3.876%), self-employed retirement contributions (SEP-IRA, Solo 401k can dramatically reduce taxable income). For exact filing, use TurboTax Self-Employed, FreeTaxUSA, or a CPA.” - q: “What’s the QBI deduction?” a: “Qualified Business Income deduction (Section 199A) lets pass-through entities — including sole proprietors filing Schedule C — deduct up to 20% of their qualified business income from federal taxable income. Subject to income limits and business-type restrictions. Not modeled here. If you qualify, your federal income tax could be substantially lower than this calculator shows.” - q: “Should I form an LLC or S-corp to reduce SE tax?” a: “Possibly. An S-corp election lets you split income between ‘reasonable salary’ (subject to FICA) and distributions (not subject to SE tax). The savings depend on your income level — generally only worth it above $50-80k of net SE income. Talk to a CPA before electing — there are payroll, compliance, and reasonable-salary requirements that can offset the savings.”

What the numbers don’t include

AMT (Alternative Minimum Tax) — affects high earners with large itemized deductions
QBI deduction — Section 199A pass-through deduction (up to 20% reduction of SE income)
Local/city income tax — NYC, San Francisco, Detroit, several others
Self-employed retirement contributions — SEP-IRA, Solo 401k can shelter major portions of income
Health insurance premiums — fully deductible for self-employed if you don’t have access to employer coverage
Quarterly estimated tax penalties — if you under-pay during the year
Quarterly estimated tax timing — covered separately in our quarterly estimated tax calculator (planned)

Sources

Last verified: April 2026.

Self-Employment Tax Calculator (Schedule SE + Federal + State)