BlogTax EstimatorSmall Business Tax Estimator: Plan Ahead for Business Taxes
Tax Planning7 min readJuly 4, 2025

Small Business Tax Estimator: Plan Ahead for Business Taxes

Small business owners face income tax, self-employment tax, and potentially state business taxes. Here's how to estimate and plan for all of them.

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Small business owners (sole proprietors, single-member LLCs) pay federal income tax plus 15.3% self-employment tax on net business income. Effective planning includes quarterly estimated payments, maximizing business deductions, contributing to a solo 401(k) or SEP-IRA, and considering an S-Corp election above ~$80,000 net income.

The Small Business Tax Stack

Running a small business means navigating multiple tax obligations:

Federal income tax: Business profit flows to your personal return at ordinary income rates (10%–37%). Sole proprietors report on Schedule C.

Self-employment tax: 15.3% on net SE income up to $168,600 (2024), then 2.9% above that.

Quarterly estimated payments: Required if you'll owe $1,000+ in federal taxes. Four payments per year.

State business taxes: Most states tax business income through the owner's personal return, but some add franchise or gross receipts taxes.

Small businesses (fewer than 500 employees) employ 46.4% of the U.S. private workforce. Source: SBA Office of Advocacy (2023) — Source

Estimating Your Tax Liability

Step 1: Net business income = Revenue – business expenses

Step 2: SE tax = Net income × 0.9235 × 15.3%

Step 3: AGI = Net income – (half of SE tax) – other above-the-line deductions

Step 4: Taxable income = AGI – standard deduction

Step 5: Apply income tax brackets; add SE tax

Example: $100,000 net SE income, single filer

  • SE tax: $14,130
  • AGI: $100,000 – $7,065 – $14,600 = $78,335
  • Federal income tax: ~$13,200
  • Total federal tax: ~$27,330 (27% effective rate)

The average small business owner pays a combined effective federal tax rate of 25–30% on net income. Source: National Federation of Independent Business (2023) — Source

The Most Impactful Planning Strategies

Solo 401(k): Contribute as both employee ($23,000) and employer (up to 25% of net SE income) — total up to $69,000 in 2024. The single most powerful tax tool for high-income self-employed workers.

Maximize business deductions: Every legitimate deduction reduces both SE tax and income tax. Keep rigorous records.

S-Corp election: At $150,000 net income, can save $10,000–$12,000 in SE taxes annually by splitting income between salary and distributions.

An S-Corp election for a business with $150,000 net income can save approximately $10,000–$12,000 in SE taxes annually. Source: IRS S-Corp guidance — Source

QBI deduction: Deduct up to 20% of qualified business income — saves $4,400 in federal taxes on $100,000 net income at 22% bracket.

Quarterly Payment Strategy

Set aside 25–30% of net business income each month into a dedicated tax savings account. Pay quarterly from that account. See our quarterly tax calculator and self-employment tax calculator.

Also see: reduce taxable income and the tax estimator guide.

Get Started with Avenue to track business income, estimate quarterly payments, and identify tax-saving opportunities year-round.

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Frequently Asked Questions

How is small business income taxed?
Most small businesses (sole proprietors, single-member LLCs, S-Corps, partnerships) are pass-through entities — income flows to the owner's personal return and is taxed at individual income tax rates plus self-employment tax.
What business expenses are tax-deductible?
Ordinary and necessary business expenses: rent, equipment, software, professional services, marketing, business travel, vehicle (business use), home office, health insurance premiums, and retirement plan contributions.
Should my small business be an S-Corp?
An S-Corp election can reduce SE tax once net income consistently exceeds $50,000–$80,000, by splitting profits between salary (SE-taxed) and distributions (not SE-taxed). Requires payroll administration — weigh savings against complexity.

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