A sole proprietorship is an unincorporated business owned by one person. If you sell products or services and have not registered any other type of business, you are one automatically. It is the easiest structure to start. The catch is that the business is not legally separate from you, so you can be held personally liable for its debts, and you report its profit on your own tax return.
What a sole proprietorship is
The IRS defines a sole proprietor as someone who owns an unincorporated business by themselves. The one exception it names is the sole member of a domestic LLC that elects to be taxed as a corporation, who is not a sole proprietor (IRS). The SBA adds that you are automatically considered a sole proprietorship if you do business activities without registering another business type (SBA).
That covers freelancers, consultants, tradespeople and online sellers who work for themselves. You can still hire employees. A sole proprietorship is a way of owning the business, not a size limit.
Liability: what personally liable means
The SBA's wording is plain: no separate legal entity is created, and you can be held personally liable for the debts and obligations of the business. IRS Publication 583 says the same thing in fewer words: the liabilities of a sole proprietorship are your personal liabilities (IRS Publication 583).
In practice, an unpaid supplier invoice, a lease you signed for the business or a customer who sues can be collected from your personal assets, not just from what is in the business account. Two things reduce that exposure. One is business insurance, which the SBA lists as a way to cover costs from accidents, natural disasters and lawsuits. The other is a different structure, such as an LLC, which the SBA says protects you from personal liability in most instances. Neither is automatic, and insurance does not cover everything. The LLC vs sole proprietorship vs S corp guide compares the options.
How a sole proprietorship is taxed
There is no separate business income tax return. You report income or loss on Schedule C, attached to your Form 1040, and you figure self-employment tax on Schedule SE. Net profit, meaning business income minus business expenses, is included in your income on Form 1040, and the tax is figured on that profit, not on what you move to your personal account (IRS). Because nobody withholds tax from you, self-employed people generally pay through quarterly estimated payments.
| Tax | Where it is reported | When it applies |
|---|---|---|
| Federal income tax | Form 1040 with Schedule C | On net profit, every year you have a business |
| Self-employment tax (Social Security and Medicare) | Schedule SE | Net earnings from self-employment of $400 or more |
| Estimated tax | Form 1040-ES | When you expect to owe enough that payments during the year are required |
| Employment taxes | Forms 941 or 944, and 940 | Only if you have employees |
| Excise taxes | For example Form 720 | Only in certain industries or activities |
| State and local taxes | Varies by state and city | Depends on where you operate; ask your state Department of Revenue |
Sources: IRS sole proprietorships page, IRS Publication 583 (Rev. December 2024) and SBA. Rates and thresholds change, so check the official site each year.
The self-employment tax is usually the surprise for first-year owners, so it has its own page: self-employment tax: how much you pay and how to pay it.
What you must register, and what you do not
- Your own legal name. The SBA says that if you operate under your own legal name you do not need to register it anywhere (SBA).
- A different business name. A DBA (also called a trade name, fictitious name or assumed name) is registered with the state, county or city, and most states require it if you use one.
- An EIN. Not automatic. The Schedule C instructions say you need one only for a qualified retirement plan, certain employment, excise, alcohol, tobacco or firearms returns, or as a payer of gambling winnings. Otherwise you use your Social Security number.
- Licenses and permits. They depend on your activity and location, so check with your state and local government.
The order and details are in how to register a small business step by step.
Records to keep
Publication 583 says to keep your business account separate from your personal checking account, and to keep a summary of business transactions plus the invoices, receipts and canceled checks behind them. The IRS retention periods depend on your situation (IRS):
| Situation | Keep records for |
|---|---|
| Most returns | 3 years |
| You left out income that is more than 25% of the gross income on your return | 6 years |
| You claim a bad debt deduction or a loss from worthless securities | 7 years |
| Employment tax records | At least 4 years after the tax due date or payment date, whichever is later |
| You did not file a return, or filed a fraudulent one | Indefinitely |
A sole proprietor's year at a glance
- Record income and expenses as they happen. Result: you can calculate net profit at any point in the year.
- Make estimated tax payments if they apply to you. Result: no large bill, and no underpayment penalty, when you file.
- Track license and permit renewals. The SBA notes that some expire after a set period.
- File Form 1040 with Schedule C and Schedule SE. Result: income tax and self-employment tax are both settled for the year.
- Keep the records for the period in the table above.
When a sole proprietorship stops being enough
None of the IRS or SBA pages on sole proprietorships sets a revenue limit. The reasons to move on are about risk and tax: you want a legal layer between your personal assets and the business, you are adding an owner, or your profit has grown to the point where a different tax treatment is worth a conversation with a tax professional. The decision, the paperwork and the costs of each option are laid out in the LLC, sole proprietorship or S corp comparison.
Frequently asked questions
Do I have to register to be a sole proprietor?
No. The SBA says you are automatically a sole proprietorship if you do business without registering another structure, and if you use your own legal name you do not need to register it. A different business name (DBA), licenses and permits may still be required by your state, county or city.
Is a sole proprietor personally liable for business debts?
Yes. A sole proprietorship is not a separate legal entity, so the SBA says you can be held personally liable for the debts and obligations of the business.
Do sole proprietors need an EIN?
Not always. The Schedule C instructions say you need one only for a qualified retirement plan, certain employment, excise, alcohol, tobacco or firearms returns, or as a payer of gambling winnings. Some banks and licensing offices still ask for one.
How does a sole proprietor pay taxes?
You report profit or loss on Schedule C with Form 1040 and figure self-employment tax on Schedule SE. Since no one withholds tax from you, you generally make quarterly estimated payments with Form 1040-ES.
Sources: SBA: Choose a business structure · IRS: Sole proprietorships · IRS: Self-employed individuals tax center · IRS: Publication 583, Starting a Business and Keeping Records · SBA: Choose your business name · IRS: How long should I keep records? · IRS: Instructions for Schedule C (Form 1040) (2025) · SBA: Launch your business
