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🏛️ Business Tax Calculator

Get a simplified estimate of your business's income tax based on entity type — sole proprietorship, LLC, S-Corp, or C-Corp.

🏛️ Business Tax Inputs
$
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Ready to Calculate

Enter your business income and entity type, then click Calculate to see results.

Estimated Tax Results
Total Estimated Tax
—
federal/income + state
Effective Tax Rate
—
of net income
After-Tax Income
—
estimated take-home
State Tax Portion
—
of total tax
⚠️ This is a simplified planning estimate — it ignores deductions, tax credits, the QBI deduction, and the Alternative Minimum Tax, and ignores self-employment tax for pass-through owners. Consult a licensed CPA or tax professional before filing.
Tax Breakdown
ItemAmount
Guide

About the Business Tax Calculator

The Business Tax Calculator gives founders and small business owners a fast, simplified estimate of income tax owed based on entity type — sole proprietorship, partnership, S-Corp, or C-Corp. Because each entity structure is taxed differently in the US, the same net business income can result in very different tax outcomes depending on how the business is organized. This tool is built for business owners comparing entity types before incorporating, freelancers weighing an LLC vs. S-Corp election, and anyone who wants a quick planning number before talking to a professional. This is an estimate for planning purposes — consult a licensed accountant or tax professional for filing.

How It Works

For pass-through entities — sole proprietorships, single-member LLCs, partnerships, and S-Corps — profit is not taxed at the entity level. Instead, it flows through to the owner's personal tax return, so the calculator applies your entered personal effective tax rate to the net business income, plus any state tax rate. For C-Corporations, the entity itself is a separate taxpayer: the calculator applies the flat 21% U.S. federal corporate tax rate, plus your state rate, directly to net income. In both cases it also computes an effective tax rate and an estimated after-tax income figure.

Why It Matters

Entity choice is one of the biggest levers on how much of your business profit you actually keep. Pass-through taxation avoids double taxation but ties your business tax rate to your personal bracket, while C-Corp status locks in a flat 21% federal rate but exposes distributed profit to a second layer of tax at the shareholder level ("double taxation") — this calculator only estimates the entity-level tax, not the second layer. Many pass-through owners can also claim the Qualified Business Income (QBI) deduction, which can shelter up to 20% of qualified income from tax but isn't modeled here since it depends on income thresholds and business type.

Tips for Accurate Results

  • Sole proprietors and partners also owe self-employment tax on this income in addition to income tax — use the Self-Employment Tax Calculator to add that on top of this estimate.
  • S-Corp owners typically don't owe self-employment tax on distributions, only payroll tax on their reasonable salary — this calculator does not separate salary from distributions, so treat the S-Corp result as an income-tax-only estimate.
  • Enter your marginal or blended effective personal tax rate carefully — a rough guess here will skew the pass-through result more than any other input.
  • Remember the QBI deduction and other credits aren't modeled, so your real tax bill for pass-through entities is often lower than shown here.
Formula

How Business Tax is Calculated

The formula used depends on whether your entity is pass-through or a C-Corporation.

Pass-Through (Sole Prop, Partnership, S-Corp)
Income Tax = Net Business Income × Personal Effective Rate
State Tax = Net Business Income × State Rate
Total Estimated Tax = Income Tax + State Tax

C-Corporation
Federal Tax = Net Business Income × 21%
State Tax = Net Business Income × State Rate
Total Estimated Tax = Federal Tax + State Tax

Both
After-Tax Income = Net Business Income − Total Estimated Tax
Effective Tax Rate = Total Estimated Tax ÷ Net Business Income
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Pass-Through vs. C-Corp

Pass-through entities are taxed once, on the owner's personal return, at personal rates. C-Corps pay a flat 21% federal rate at the entity level, separate from the owner's personal taxes.

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Watch for Double Taxation

C-Corp profit distributed as dividends is taxed again at the shareholder level. This calculator only estimates the entity-level tax, not the second layer paid by shareholders.

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QBI & Deductions Not Modeled

The Qualified Business Income deduction, credits, and the Alternative Minimum Tax can significantly change a real tax bill. This tool is a starting estimate, not a substitute for professional advice.

FAQ

Frequently Asked Questions

Common questions about business entity taxation

How are pass-through entities taxed differently from C-Corps?
Pass-through entities — sole proprietorships, partnerships, and S-Corps — don't pay income tax at the entity level. Profit flows through to the owner's personal tax return and is taxed at the owner's personal income tax rate. A C-Corp is a separate taxpayer: it pays a flat 21% federal corporate rate on its profit, and if that profit is later distributed to shareholders as dividends, the shareholders pay tax on it again on their personal returns.
What is double taxation?
Double taxation refers to C-Corp profit being taxed twice: once at the entity level (21% federal corporate rate plus any state corporate tax) and again at the shareholder level when profit is distributed as dividends. Pass-through entities avoid this because profit is only taxed once, on the owner's personal return.
What is the Qualified Business Income (QBI) deduction?
The QBI deduction lets many owners of pass-through businesses (sole proprietorships, partnerships, S-Corps) deduct up to 20% of their qualified business income on their personal tax return, subject to income thresholds and business-type limitations. This calculator does not model QBI — consult a CPA to see if you qualify, since it can meaningfully lower your effective rate.
Does entity type affect self-employment tax?
Yes. Sole proprietors and partners generally owe self-employment tax on all their net business earnings. S-Corp owners who work in the business typically only owe payroll (FICA) tax on their reasonable salary, not on additional profit distributions — this is a common reason businesses elect S-Corp status. C-Corp owners who are employees pay payroll tax only on wages.
Is this calculator accurate enough to file my taxes?
No — treat it as a simplified planning estimate only. It ignores deductions, tax credits, the QBI deduction, the Alternative Minimum Tax, and state-specific rules. For actual filing, use IRS-approved tax software or consult a licensed CPA or tax professional.
What entity types can I select?
Four options: Sole Proprietorship / Single-Member LLC, Partnership / Multi-Member LLC, S-Corporation, and C-Corporation. The first three are pass-through entities taxed at your personal rate; C-Corp uses the flat 21% federal corporate rate instead.
How do I estimate my personal effective tax rate?
Your effective tax rate is your total federal income tax divided by your total taxable income — not your marginal bracket. You can pull a rough figure from last year's tax return or use the site's Tax Calculator to estimate it before entering it here.
Does this calculator include self-employment tax?
No. It only estimates income tax (your personal rate or the 21% corporate rate) plus state tax. Sole proprietors and partners separately owe self-employment tax on their net earnings — use the site's Self-Employment Tax Calculator to add that on top of this estimate.
Why does the personal rate label change to "not used for C-Corp" when I select that entity?
C-Corps aren't pass-through entities, so profit isn't taxed at your personal rate — the calculator instead applies the flat 21% federal corporate rate regardless of what's in the personal rate field, and the label updates to remind you that input is ignored for that entity type.
How is state tax factored into the estimate?
The state rate you enter is applied directly to your net business income and added to the federal or personal tax to produce the total estimated tax, for every entity type. Enter your state's corporate or personal income tax rate depending on which applies to your entity.
Can this calculator help me decide whether to elect S-Corp status?
It can give you a rough income-tax comparison between entity types, but it doesn't model the salary-vs-distribution split that drives most S-Corp savings on self-employment tax. Use it alongside the Self-Employment Tax Calculator and a CPA before making an election.
Can I export or save my results?
Yes. Click "Export Result" to download a plain-text summary of your entity type, net income, and estimated tax breakdown for your records.

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