In the US there is no revenue figure at which a sole proprietorship has to become something else. The IRS and SBA pages on these structures set no revenue cap. What pushes people to change is risk and tax: an LLC adds a legal layer between your personal assets and the business, while an S corporation is a tax election that changes how the owner's pay is taxed. A default one-owner LLC is taxed exactly like a sole proprietorship.
No revenue limit, so what should trigger a change?
The thresholds that do exist are about something else. Self-employment tax starts at $400 of net earnings, and S corporation status has eligibility rules such as a cap on shareholders. SBA size standards, which are stated in employees or average annual receipts and vary by industry, decide who counts as a small business for government contracting programs, not what legal structure you may use. The NAICS code guide covers that side.
These are better triggers than a sales number:
- You have contracts, a lease, inventory or clients where a loss could reach your personal savings or home.
- You are adding a co-owner.
- Your profit is steady and well above what you need to live on, and you want a tax professional to model another setup.
Hiring employees is not on the list. A sole proprietor can have employees.
Sole proprietorship vs LLC vs S corporation
| Question | Sole proprietorship | LLC (one owner, default) | S corporation election |
|---|---|---|---|
| How it starts | Automatically, when you do business | You file articles of organization with the state | An eligible corporation or LLC files Form 2553, signed by all shareholders |
| Personal liability | You can be held personally liable | Owners are generally protected | Owners are not personally liable |
| Federal income tax | Schedule C with Form 1040 | Disregarded as separate from its owner; reported on the owner's return | Income passes through; the company files Form 1120-S and shareholders report on Schedule E |
| Self-employment or payroll tax | Self-employment tax on net earnings | Same self-employment tax as a sole proprietor | Owners who work in the business must be paid reasonable compensation as wages |
| Extra paperwork | None beyond your return | State filing; ongoing rules vary by state | Payroll filings (Forms 941 and 940), Form 1120-S and Schedule K-1s |
| Eligibility limits | None | None | Domestic corporation, up to 100 shareholders, one class of stock, limits on who can own it |
| Usually considered when | Low-risk work, simple setup, just starting | You want liability protection without changing how you pay tax | Steady profit, and payroll for yourself is worth the cost |
Sources: SBA business structures page, IRS pages on LLCs and S corporations. The last row is a general guideline, not an official rule. Rules vary by state, so confirm with your state and a tax professional.
What an LLC changes, and what it does not
The SBA says an LLC protects you from personal liability in most instances, so personal assets are generally shielded from business debts and lawsuits (SBA). For tax, an LLC is whatever the IRS default says. A single-member LLC is disregarded as separate from its owner unless it elects corporate treatment, and a domestic LLC with at least two members is classified as a partnership (IRS).
- Changes: the liability picture, and a state filing with its own requirements. For employment taxes the LLC is treated as a separate entity, so it reports and pays them under its own name and EIN (IRS).
- Does not change: the owner of a single-member LLC still pays self-employment tax on net earnings, exactly like a sole proprietor, and the activity is reported on the owner's return, on Schedule C, E or F depending on the activity. The self-employment tax guide shows the math.
- Is not absolute: the SBA's wording is "in most instances", not "always". Keeping business and personal money apart in a separate business account is part of running the company properly.
An LLC can also file Form 8832 to elect corporate classification, or Form 2553 to be taxed as an S corporation if it meets the requirements.
S corporation: a tax election with strings attached
An S corporation passes income, losses, deductions and credits through to its shareholders, who pay tax on their personal returns. The company itself needs a Form 1120-S every year (IRS). The requirements are specific:
- It must be a domestic corporation, or an entity eligible to be treated as one.
- Shareholders can be individuals, certain trusts and estates. Partnerships, corporations and nonresident aliens cannot be shareholders.
- No more than 100 shareholders, and only one class of stock.
- Form 2553 is due no more than 2 months and 15 days after the start of the tax year the election takes effect, or any time during the tax year before the election takes effect. Late-election relief exists in some cases (IRS).
The part that surprises people is pay. The IRS says an S corporation must pay a shareholder-employee reasonable compensation for services before making non-wage distributions, and it can reclassify payments labeled as distributions as wages. It looks at training and experience, duties, time and effort, what comparable businesses pay and similar factors (IRS). Any savings come from how pay is split between wages and distributions, and that split has to hold up. The SBA also notes that some states tax S corporations differently.
Five questions before you switch
- What could someone collect from me personally? If the answer is your home or savings, look at an LLC and at insurance.
- Do I need a co-owner? More than one member changes the default tax treatment to a partnership.
- Am I willing to run payroll for myself? That is the practical price of an S election.
- What does my state charge to form and maintain an entity? Filing and ongoing rules vary by state, so check your state's business filing office.
- What do my real numbers say? Have a tax professional compare both scenarios.
How to move from sole proprietor to LLC
- Form the LLC with your state. Result: the LLC exists as a legal entity. The small business registration guide covers name checks and filings.
- Decide on an EIN. A single-member LLC with no employees and no excise tax liability generally does not need one, but you may want one for a bank account. If you hire, the LLC uses its own EIN for employment taxes.
- Update what carries your name. Ask your licensing offices, bank, insurer and key clients what they need.
- Keep filing as before. Result: a default LLC still reports on your own return.
- Add the S election only if the numbers justify it. Meet the Form 2553 deadline for the year you want it.
New to all of this? Start with the sole proprietorship guide. Tax rules change, so check irs.gov and your state for the current year.
Frequently asked questions
Is there an income limit for a sole proprietorship?
The IRS and SBA pages on sole proprietorships set no revenue limit. Other thresholds exist, such as self-employment tax starting at $400 of net earnings and the eligibility rules for an S corporation, but none of them forces you to change structure.
Does an LLC lower my taxes?
Not by default. The IRS treats a single-member LLC as disregarded from its owner, who reports the income on their own return and pays self-employment tax like a sole proprietor. The main change is liability protection.
When does an S corporation make sense?
It is usually worth modeling when profit is steady and well above what you need to live on, because paying yourself a reasonable salary through payroll adds cost and paperwork. The effect depends on your numbers and your state, so have a tax professional compare the options.
When do I have to file Form 2553?
The IRS instructions say no more than 2 months and 15 days after the beginning of the tax year the election is to take effect, or any time during the tax year before the election takes effect. Late-election relief may be available.
Sources: SBA: Choose a business structure · IRS: LLC filing as a corporation or partnership · IRS: Single member limited liability companies · IRS: S corporations · IRS: S corporation compensation and medical insurance issues · IRS: Instructions for Form 2553 (12/2020) · IRS: Sole proprietorships · SBA: Size standards
