Small Business & Self-Employment
Running your own business or working for yourself changes how you pay tax. These guides cover estimated payments, self-employment tax, deductions, and the records you need to keep.
8 guidesReviewed for the 2025 tax year
New to this topic? Begin here.
Questions this section answers
- Do I need to pay quarterly estimated taxes?
- What can I deduct as a small business owner?
- Am I an employee or an independent contractor?
- What is self-employment tax and how is it calculated?
- Do I qualify for the home office deduction?
- How do I fill out Schedule C?
- Can I take the 20% QBI deduction?
- Can I deduct equipment in the first year with Section 179 or bonus depreciation?
- Is my side activity a hobby or a business?
Every guide in this topic
Quarterly estimated taxes: who pays and how to calculate
Who must pay estimated taxes, the quarterly due dates, how to calculate each payment, and how to avoid underpayment penalties.
What can I deduct as a small business owner?
The main Schedule C deductions, including home office, vehicle, equipment, and meals, plus what you cannot deduct.
What is self-employment tax and how does it work?
Social Security and Medicare tax for the self-employed: the $400 rule, the 15.3% rate, 92.35% of net earnings, and Schedule SE.
Home office deduction — do I qualify?
Regular and exclusive business use, principal place of business, the exceptions, and the simplified $5-per-square-foot option.
The QBI Deduction: 2025 and 2026 Rules
The 20% qualified business income deduction: what counts, 2025 and 2026 thresholds, service businesses, and the 2026 $400 minimum.
Schedule C Explained: Self-Employment Income and Expenses
How Schedule C works for 2025 and 2026: gross receipts and Forms 1099, expense lines, home office, mileage rates, profit and losses.
Section 179 and Bonus Depreciation: 2025 and 2026 Rules
Writing off business equipment in year one: 2025 and 2026 section 179 limits, 100% bonus depreciation, business use, and Form 4562.
Hobby or Business? How Side Income Is Taxed in 2025 and 2026
Hobby vs. business: profit-motive factors, the 3-of-5-year presumption, Form 5213, Schedule C vs. Schedule 1, and hobby expenses.
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