Business Tax Calculator 2026
Calculate self-employment tax, QBI deduction, quarterly estimated payments, and see if an S-Corp election could save you thousands. For freelancers, consultants, and small business owners.
What This Business Tax Calculator Does
This calculator estimates the federal income tax liability for small business owners, including the Qualified Business Income (QBI) deduction (Section 199A), which allows eligible pass-through businesses to deduct up to 20% of qualified business income. It handles sole proprietors, single-member LLCs, partnerships, S-Corps, and other pass-through entities where business income flows to the owner's personal return.
How Small Business Income Is Taxed
Most small businesses in the US are pass-through entities: sole proprietorships (Schedule C), partnerships, S-Corporations, and LLCs taxed as any of these. Business income passes through to the owner's personal tax return and is taxed at individual rates. This is different from C-Corporations, which pay a flat 21% federal corporate tax rate on profits before any distribution.
The QBI Deduction (Section 199A)
Pass-through business owners can deduct up to 20% of qualified business income (QBI), potentially reducing the effective tax rate significantly. For a business owner in the 24% bracket with $100,000 in QBI, the deduction reduces taxable income by $20,000, saving $4,800 in income tax (24% × $20,000).
The deduction has income limitations and phase-outs, and certain "specified service trades or businesses" (SSTB) — law, finance, health, consulting, and similar fields — face additional restrictions at higher income levels. For 2024, the deduction phase-out for SSTBs begins at $182,050 (single) and $364,200 (married).
S-Corp Tax Strategy
A common strategy for higher-earning self-employed individuals: elect S-Corp status, pay yourself a "reasonable" salary (subject to full payroll taxes), and take additional business income as a distribution (not subject to self-employment tax). The strategy saves on SE tax but adds complexity: payroll setup, quarterly payroll deposits, W-2 filing, corporate return (Form 1120-S), and potentially state fees. The math usually pencils out above $60,000–$80,000 in net business income.
Key Deductible Business Expenses
- Home office (actual expense or $5/sq ft simplified, max $1,500)
- Vehicle: business mileage at $0.67/mile (2024) or actual expense method
- Equipment and technology (may qualify for immediate expensing under Section 179)
- Professional development, continuing education, subscriptions
- Health insurance premiums (deducted as an adjustment to income)
- Retirement contributions (Solo 401k, SEP-IRA)
- Business insurance, software, advertising, professional fees
Tips and Best Practices
- Open a Solo 401(k) if self-employed with no employees — you can contribute as both employee ($23,000) and employer (up to 25% of net SE income), with a combined limit of $69,000 in 2024.
- Maintain meticulous records — business deductions require documentation. Use dedicated business accounts and credit cards; keep all receipts.
- Consider quarterly estimated payments — business income has no withholding. Underpayment penalties apply if you don't pay at least 90% of current year liability or 100%/110% of prior year liability.
Related Calculators
- Self-Employment Tax Calculator — SE tax component of business income.
- Income Tax Calculator — full federal income tax including business income.
- 401(k) Calculator — model Solo 401(k) contributions.
Frequently Asked Questions
Do I need a separate EIN for my business?
Sole proprietors with no employees can use their SSN. Anyone with employees, or any business organized as an LLC/S-Corp/C-Corp, needs an EIN (Employer Identification Number). Getting an EIN from the IRS is free and takes minutes at irs.gov.
Can I deduct startup costs?
Yes — up to $5,000 in startup costs in the first year, with the remainder amortized over 15 years. Organizational costs (LLC filing fees, attorney fees) are treated separately with the same $5,000/$remainder structure.
When should a small business consider incorporating?
LLC formation makes sense relatively early for liability protection. S-Corp election for tax purposes makes sense when net income is consistently above $60,000–$80,000 and the SE tax savings exceed the cost of S-Corp administration. C-Corp status is rarely optimal for small businesses due to double taxation on distributions.
Key Takeaways
Small business taxation involves both the complexity of pass-through structures and the opportunity to reduce taxable income significantly through legitimate deductions and retirement contributions. The QBI deduction alone can reduce a pass-through owner's effective tax rate by 4–5 percentage points — a benefit that requires no additional spending, just proper structuring. Combined with pre-tax retirement contributions and systematic expense tracking, the tax position of a well-run small business can be substantially better than an equivalent W-2 employee, despite the added administrative burden.