Definition
The default business structure for one person earning money on their own: no entity is formed, and legally the owner and the business are the same. Profit is reported on Schedule C of the owner's personal return and is subject to both income tax and self-employment tax. The owner is personally responsible for every debt and lawsuit of the business.
Why it matters
Every freelancer and side-hustler is a sole proprietor from the first dollar, whether they realize it or not, which is why quarterly estimated taxes and self-employment tax surprise so many first-year earners. The unlimited personal liability is the reason people eventually form an LLC.
Example
A woodworker sells $45,000 of furniture in a year and spends $15,000 on lumber, tools, and a market booth. The $30,000 of net profit goes on Schedule C and owes income tax plus a bit over $4,000 of self-employment tax. If a customer is injured by a defective chair and wins a $100,000 judgment, the woodworker's personal savings and car are on the line.
Put it into practice
Related terms
This definition is educational, not financial, legal, or tax advice. U.S. rules and limits change; verify time-sensitive details with official sources. See our disclaimer.