To convert a sole proprietorship to an S corp, you form a new legal entity (a corporation or an LLC) with your state, get a new EIN for it, file IRS Form 2553 to elect S corporation tax treatment, transfer your business assets and contracts into the entity, and start paying yourself a reasonable W-2 salary through payroll. The payoff is self-employment tax: instead of paying 15.3% Social Security and Medicare on your entire net profit, you pay employment taxes only on your salary, and the rest comes out as distributions that escape that 15.3%.
Is It Actually Worth It Yet
S corps carry real compliance costs a sole proprietorship doesn’t: payroll software or a service, a separate corporate tax return each year, and in many states an annual report or franchise fee. Expect $1,500 to $3,000 per year at a minimum. If your profit is too low, those costs eat the tax savings.
The rough threshold: the election starts to pay off once net profit consistently runs somewhere above $60,000 to $80,000 per year. Between $40,000 and $60,000 the math is close, and it’s worth running the numbers with a tax professional before committing. Below that, stay a sole proprietor.
One variable to check before you decide: the Section 199A qualified business income deduction, which lets eligible owners deduct up to 20% of qualified business income, was scheduled to expire for tax years beginning after December 31, 2025.1Internal Revenue Service. Qualified Business Income Deduction Congressional action may extend it. Confirm whether it applies to your tax year before you factor it into the comparison.
Corporation or LLC With an S Election
“S corp” is a tax status, not an entity type. You can get there by forming a state-law corporation, or by forming an LLC and electing to have it taxed as an S corporation. The IRS allows any entity eligible to be treated as a corporation to file the S election.2Internal Revenue Service. About Form 2553, Election by a Small Business Corporation
For most sole proprietors, the LLC route is simpler. A corporation requires a board of directors, officer elections, bylaws, annual meetings, and meeting minutes kept in a corporate minute book. Skip those formalities and you can weaken the liability protection the structure was supposed to give you. An LLC is governed by an operating agreement and has far fewer maintenance requirements in most states. Both provide the same personal liability protection, and both get the same S corp tax treatment once you file Form 2553.
If you go the LLC route, you don’t need to file Form 8832 first. A single-member LLC is disregarded for federal tax purposes by default, and filing Form 2553 alone causes the IRS to treat it as a corporation that has elected S status.3Internal Revenue Service. About Form 8832, Entity Classification Election
Form the Entity With Your State
The new entity is created by filing formation documents with the Secretary of State (or equivalent agency) in the state where your business operates. For a corporation, that’s Articles of Incorporation. For an LLC, it’s Articles of Organization or a Certificate of Formation, depending on the state.
Before filing, search the state’s business name database to confirm your name is available. You’ll also designate a registered agent inside the state, meaning a person or service authorized to accept legal documents on the entity’s behalf. The filing itself typically lists the entity name, the registered agent’s address, and for a corporation, the number of authorized shares.
Filing fees generally run from about $50 to $300, though a few states charge more. Once the state approves the filing, you have a legally separate entity.
Get a New EIN
The new entity needs its own Employer Identification Number. You can’t reuse the sole proprietorship’s EIN or your Social Security number. The IRS online application issues the number immediately at no cost.4Internal Revenue Service. Get an Employer Identification Number If you’re outside the U.S. or prefer paper, you can submit Form SS-4 by fax or mail.5Internal Revenue Service. Instructions for Form SS-4 Every bank account, tax return, and payroll filing for the business will use this new EIN going forward.
File Form 2553 to Elect S Status
A newly formed corporation defaults to C corporation tax treatment, which means the entity pays income tax and owners get taxed again on distributions. The S election eliminates that double taxation by passing income through to your personal return. You make the election by filing IRS Form 2553.6Internal Revenue Service. Instructions for Form 2553
Eligibility
The entity must be domestic and meet all of the following:7Office of the Law Revision Counsel. 26 USC 1361 – S Corporation Defined
- No more than 100 shareholders. Family members and their estates count as a single shareholder.
- Shareholders must be U.S. citizens or residents, certain trusts, or estates. Partnerships, other corporations, and nonresident aliens cannot hold shares.
- Only one class of stock, though voting-rights differences among common shares are permitted.
- Certain financial institutions, insurance companies, and domestic international sales corporations cannot elect S status.
For a sole proprietor with no other owners, none of these are usually a problem.
The Deadline
To make the election effective for the current tax year, file Form 2553 no later than two months and 15 days after the tax year begins, which is March 15 for calendar-year businesses. You can also file at any time during the preceding tax year.8Office of the Law Revision Counsel. 26 USC 1362 – Election, Revocation, Termination File after the deadline and the election automatically applies to the following tax year.
All shareholders must sign the form. As the sole owner, you sign as the only shareholder.
If You Miss the Deadline
The IRS offers late-election relief under Revenue Procedure 2013-30 if you file within three years and 75 days of the intended effective date. You need to show reasonable cause for the delay and demonstrate that the business and all shareholders reported income consistently with S corp status for the period in question. Write “FILED PURSUANT TO REV. PROC. 2013-30” across the top of the Form 2553.6Internal Revenue Service. Instructions for Form 2553
Transfer Assets Into the Entity
Once the entity exists and has its EIN, move the sole proprietorship’s assets into it. The standard approach is to contribute assets (equipment, inventory, accounts receivable, intellectual property, customer lists) in exchange for stock in the corporation, or a membership interest in the LLC.
Document the transfer with a bill of sale for tangible property and an assignment agreement for intangibles like contracts, trade names, and IP. Leases for office space or equipment need to be formally assigned or re-executed in the new entity’s name.
Section 351 of the Internal Revenue Code makes this a non-taxable event: no gain or loss is recognized when you transfer property to a corporation solely in exchange for stock, as long as you control the corporation immediately after the exchange.9Office of the Law Revision Counsel. 26 US Code 351 – Transfer to Corporation Controlled by Transferor As sole owner, you meet the control test automatically, and the entity takes over your existing tax basis in the assets.
Existing liabilities like business loans or lines of credit need formal transfer too. Lenders typically require an assumption agreement or loan modification to shift the debt from you personally to the new entity, and they may re-underwrite the credit based on the entity’s financials. This is often where conversions stall.
Set Up Payroll and Pay Yourself Reasonably
This is where the tax savings actually happen, and where the IRS pays the closest attention. As a sole proprietor, your entire net profit is subject to self-employment tax at 15.3% (Social Security 6.2% each side plus Medicare 1.45% each side).10Internal Revenue Service. Topic No. 751, Social Security and Medicare Withholding Rates As an S corp owner-employee, only your W-2 salary is subject to those employment taxes. Distributions of remaining profit are not.
The catch is reasonable compensation. The IRS requires any shareholder who performs services for the S corp to receive reasonable pay before taking distributions. Pay yourself a $20,000 salary for work that would command $80,000 on the open market, take $60,000 as a “distribution,” and the IRS will reclassify those distributions as wages, then hit the corporation with back taxes, interest, and penalties.
Courts and the IRS look at factors like your training and experience, the duties and hours you actually put in, what comparable businesses pay for the role, the company’s dividend and distribution history relative to wages, and whether the salary was set through a deliberate, documented process.11Internal Revenue Service. Wage Compensation for S Corporation Officers Research salary data for your role and industry, set your compensation at a defensible level, and document the reasoning in a corporate resolution. Lowballing salary is the single most common audit trigger for S corp owner-employees.
On mechanics: register the corporation as an employer with your state workforce agency for unemployment insurance, then set up a payroll system (or hire a service) to process your W-2 wages under the new EIN. The corporation withholds federal income tax, the employee’s share of FICA, and applicable state taxes, then remits those amounts along with the employer’s share. Payroll taxes get reported quarterly on Form 941,12Internal Revenue Service. Topic No. 758, Form 941 and Form 944 federal unemployment tax annually on Form 940, and you issue yourself a W-2 at year end.13Internal Revenue Service. S Corporations
Close Out the Sole Proprietorship Side
Open new bank accounts in the entity’s legal name using the new EIN. Every business transaction runs through those accounts from here on. Commingling personal and business money is the fastest way to lose the liability protection the new structure was supposed to give you.
Update your business licenses and permits with state, county, and municipal authorities. Operating under the old sole proprietorship name and EIN after the conversion can trigger fines and creates a messy audit trail. Notify vendors, suppliers, and customers so contracts, invoices, and payments start reflecting the new entity.
If you formed a corporation rather than an LLC, hold an organizational meeting of directors and shareholders, adopt bylaws, elect officers, record all of it in a corporate minute book, and issue yourself stock certificates for the contributed assets. Courts do look at whether owners actually maintained those records when deciding whether creditors can reach personal assets.
What You’ll File Every Year Now
Federal filing obligations go up substantially. The annual income tax return is Form 1120-S, due by the 15th day of the third month after the tax year ends; for calendar-year S corps, the 2025 return is due March 16, 2026, because March 15 falls on a Sunday.14Internal Revenue Service. Instructions for Form 1120-S (2025) Form 7004 gets you a six-month extension to file, but any tax owed is still due by the original date.
The S corp itself generally doesn’t pay federal income tax. It passes income, losses, deductions, and credits through to you on Schedule K-1, which you report on your personal Form 1040 (Schedule E).15Internal Revenue Service. Shareholder’s Instructions for Schedule K-1 (Form 1120-S) You no longer file Schedule C for this business after the conversion is complete.16Internal Revenue Service. About Schedule C (Form 1040), Profit or Loss from Business (Sole Proprietorship) Convert mid-year and you’ll file a final short-year Schedule C for the sole proprietorship period plus Schedule E for the S corp remainder.
On top of the income return, you’ll file Form 941 quarterly, Form 940 annually, and W-2s and W-3s at year end. Most states also require an annual report or franchise tax filing for the entity, with fees that vary widely. Some states do not automatically honor the federal S election and require a separate state-level filing, so check with your state’s tax authority to avoid a surprise state-level corporate tax bill.
If You Change Your Mind Later
S corp status isn’t permanent. If income drops, compliance becomes a drag, or your ownership structure changes, you can revoke the election with the consent of shareholders holding more than half of the shares. File the revocation statement with the IRS by March 15 and it takes effect January 1 of that year; file after March 15 and it kicks in the following January 1, unless you specify a later date.8Office of the Law Revision Counsel. 26 USC 1362 – Election, Revocation, Termination
The catch: once the S election is revoked or terminated, the corporation and any successor generally cannot re-elect S status for five tax years without IRS consent. That makes revocation a decision worth thinking through, not a reaction to a single slow year.