You do not convert a sole proprietorship the way you convert a file. You form a new LLC with your state, then move the business into it: the bank account, licenses, contracts and equipment. The SBA says a sole proprietorship does not produce a separate business entity, so there is no entity to dissolve. What you have are old accounts and registrations to close, update or reissue. Whether to switch at all is a different question, answered in the LLC vs sole proprietorship vs S corp guide. This page assumes you decided yes and want the steps in order, with the traps.
The order that avoids rework
- Check your state's filing steps and the name. Result: you know what your state requires and that the name is available. The registration guide covers name checks.
- Choose a registered agent. Result: an in-state address that can receive legal papers. The SBA says you need one before you file.
- File the articles of organization. Your state may call the document something else. Result: the LLC exists once the state accepts it.
- Write the operating agreement. Result: a signed document that says who owns the LLC and how decisions are made.
- Settle the EIN question. Result: you know whether you keep your number, get a new one, or need none.
- Open a bank account in the LLC's name. Result: business money is separate from yours from the first day.
- Move licenses, permits and tax accounts. Result: each issuing office has told you what carries over and what is reissued.
- Move contracts and customers. Result: clients pay and sign with the LLC.
- Update insurance, titles and online accounts. Result: nothing important is left in your personal name by accident.
Steps 1 to 4: the state filing and the operating agreement
The SBA describes articles of organization as a simple document with the basics of your LLC, typically the company name, address, member names and registered agent, and notes that filing requirements and fees vary by state (SBA). Some states add steps. New York requires articles filed with its Department of State, then publication of a copy or notice in two newspapers for six consecutive weeks and a Certificate of Publication filed afterward. The LLC's authority to do business is suspended if that is not done within 120 days (New York Department of State). Check your own state's business filing office before you pay anyone to file for you.
The operating agreement is the document people skip. The SBA says whether one is required depends on the state, that it is widely recommended even where it is not, and that without one your state's default rules apply, which it calls too general to rely on. New York does require a written agreement, adopted before filing, at filing or within 90 days after, and it is not filed with the state. Even as the only member, write down who owns the LLC, how you take money out, and what happens if you add an owner. The SBA warns that some states may require an LLC to be dissolved and re-formed when members change, unless the agreement covers buying, selling and transferring ownership.
Step 5: the EIN, case by case
The SBA says that in general you need a new EIN when ownership or structure changes, and sends you to the IRS for specifics. The IRS page is more precise, and it was reviewed in July 2026 (IRS):
| Your situation | EIN |
|---|---|
| One-owner LLC, default tax treatment, no employees, no excise taxes | No new EIN needed. You can keep using your Social Security number or the EIN you already have as a sole proprietor. The LLC can get its own if a bank or state law asks for one. |
| You have employees, or file excise taxes | The LLC is treated as a separate entity for employment taxes and must use its own name and EIN (IRS). Plan the switch of payroll with your payroll provider, and see the hiring guide. |
| You add a second owner | The IRS says a sole proprietor who forms a partnership needs a new EIN. Ask a tax professional how a multi-member LLC is classified before you add a member. |
| The LLC later elects corporate or S corporation tax treatment | No new EIN is needed just for the election, if the LLC already has one. |
Applying is free on irs.gov, and the Form SS-4 instructions (rev. December 2025) say EIN issuances are limited to one per responsible party per day. A disregarded LLC without its own EIN uses the owner's name and number for federal income tax purposes.
Steps 6 to 9: moving accounts, permits, contracts and money
| Item | What to do |
|---|---|
| Bank account | Open one in the LLC's name. The SBA lists the usual documents as an EIN (or SSN for a sole proprietor), the formation documents, ownership agreements and a business license, and says a separate account helps keep your funds apart from the business's. |
| Licenses and permits | Ask each issuing office whether the license can be amended or must be reissued to the LLC. The SBA says some expire after a set period, so track renewals, and suggests starting with your Secretary of State's website. |
| Sales tax permit | Do not assume it carries over. Texas says a permit cannot be transferred from one owner to another, that a business needs a new one if ownership changes, including a sole proprietor who incorporates, and that the old one should be closed when no longer needed (Texas Comptroller). California tells permit holders to contact its tax agency when ownership changes. Ask your state before you close anything. |
| Client and vendor contracts | Ask each client to sign a new agreement or acknowledge the LLC as the contracting party, instead of assuming old agreements follow the business. For a lease, loan or large contract, read the assignment clause and consider a lawyer. |
| Invoices and Form W-9 | Bill in the LLC's name (see the invoice guide). On Form W-9 for a single-member LLC, enter the owner's name on line 1, the LLC's name on line 2 and the owner's SSN or EIN. The LLC's own EIN goes there only if it is classified as a corporation or partnership. |
| Insurance | Ask your insurer to put the LLC on the policy. The SBA says to insure against things you could not pay for on your own, and notes some coverage may be legally required. |
| DBA, equipment, vehicles, domain, phone number | List what the business uses, decide what moves, and update titles and registrations. If you registered a DBA, ask the office that holds it what changes. |
After the switch: what stays the same
- Federal income tax. A single-member LLC is disregarded as separate from its owner, so you keep reporting on Schedule C with your Form 1040 and pay self-employment tax as before (how that tax works).
- Liability protection has limits. The SBA says an LLC protects you from personal liability in most instances, not all. Pay business costs from the LLC account and keep personal spending out of it.
- No beneficial ownership report. FinCEN says U.S. companies are exempt from beneficial ownership information reporting under a final rule announced August 11, 2026, so a new LLC formed in a US state does not file a BOI report (FinCEN). Older articles still describe the earlier deadlines.
- Ongoing state filings. Annual or biennial reports and fees vary by state. Ask your state's filing office what applies and put the dates on your calendar.
Rules and fees change, so confirm each step on your state's official site and irs.gov, and ask a CPA or attorney before you move contracts or assets that matter.
Frequently asked questions
Do I need a new EIN when I form an LLC?
Not always. The IRS page lists a one-owner LLC with default tax treatment, no employees and no excise taxes among the cases that can keep using a sole proprietor's EIN. You do need the LLC's own EIN if it must file employment or excise taxes.
Do I need an operating agreement for a one-person LLC?
It depends on the state. The SBA says the requirement varies and that having one is widely recommended; New York, for example, requires a written agreement within 90 days after filing.
Does the LLC change how I file federal taxes?
Not by default. A single-member LLC is disregarded as separate from its owner, so the business is reported on your own return, usually on Schedule C, and self-employment tax works as before.
Do I need to file a BOI report for a new LLC?
FinCEN says U.S. companies are exempt under a final rule announced August 11, 2026, so a US-formed LLC does not file one. Check fincen.gov/boi in case that changes.
Can I keep my old business license and sales tax permit?
Do not assume so. Texas, for example, says a sales tax permit cannot be transferred to a new owner and a business needs a new permit when ownership changes. Ask each issuing office what it requires for the LLC.
Sources: IRS, When to get a new EIN · IRS, Single member limited liability companies · IRS, Instructions for Form SS-4 (rev. December 2025) · IRS, Form W-9 · SBA, Choose a business structure · SBA, Basic information about operating agreements · SBA, Open a business bank account · SBA, Apply for licenses and permits · New York Department of State, Forming a limited liability company in New York · Texas Comptroller, Sales and use tax FAQ: permits · California Department of Tax and Fee Administration, Obtaining a seller's permit · FinCEN, Beneficial ownership information reporting
