In most cases you do need a new EIN when converting an LLC to a C corp, but not always. The deciding factor is how your LLC was being taxed at the moment of conversion. If it was taxed under the default rules as a disregarded entity or a partnership, the IRS treats the conversion as the birth of a new taxable entity and expects a new EIN. If your LLC had already elected corporate tax treatment on Form 8832 before the conversion, you keep the EIN you have.
When a New EIN Is Required
A single-member LLC is treated as a disregarded entity for federal income tax purposes, and a multi-member LLC is treated as a partnership.1Internal Revenue Service. LLC Filing as a Corporation or Partnership When either one becomes a C corporation, the federal tax classification changes in a way the IRS treats as the formation of a new entity.
The IRS guidance on EINs says a new number is required when you “terminate an existing LLC and form a new corporation,” and separately when a partnership “incorporates.”2Internal Revenue Service. When to Get a New EIN Because a multi-member LLC defaults to partnership treatment, incorporating it falls under the partnership rule. A single-member LLC moving from disregarded status to filing its own corporate return falls under the LLC rule.
This holds whether your state allows a statutory conversion (the LLC continues under a new corporate form) or you dissolve the LLC and form a new corporation outright. The IRS cares about the change in federal tax classification, not the state-law mechanics.
When You Can Keep Your Existing EIN
If your LLC was already taxed as a corporation before the legal conversion, you do not need a new EIN. An LLC can elect corporate tax treatment at any time by filing Form 8832, Entity Classification Election.3Internal Revenue Service. About Form 8832, Entity Classification Election Changing a tax election by itself does not trigger a new EIN.2Internal Revenue Service. When to Get a New EIN
The Form 8832 instructions put it plainly: “Any entity that has an EIN will retain that EIN even if its federal tax classification changes,” and the form warns against applying for a new EIN when an existing entity is simply changing classification.4Internal Revenue Service. Form 8832, Entity Classification Election Once the IRS already recognizes your LLC as a corporation for tax purposes, a later state-level conversion to a formal C corporation does not change the tax structure in a way that calls for a new number.
Electing corporate tax treatment first, then converting the entity at the state level, is a common sequence for exactly this reason. Keeping the same EIN preserves your IRS account history, your bank accounts, and your vendor records.
Getting the New EIN
If your conversion does require a new EIN, the IRS online application is the fastest path. It’s free, takes about 15 minutes, and issues the number immediately on approval. The tool is open Monday through Friday from 6:00 a.m. to 1:00 a.m. Eastern, Saturday from 6:00 a.m. to 9:00 p.m., and Sunday from 6:00 p.m. to midnight. There is no save function, so have the new corporation’s information ready before you start.5Internal Revenue Service. Get an Employer Identification Number
You can also submit Form SS-4 by fax (processed in about four business days) or by mail (four to five weeks). Whichever method you use, print and keep the confirmation. You’ll need the new number for the corporation’s first tax return, payroll setup, and bank updates.
Tax Returns in the Conversion Year
A mid-year conversion splits your filing obligations. The old entity files a final return covering the year through the day before conversion. The new corporation files a first return from the conversion date forward.
Final Return Under the Old EIN
A multi-member LLC taxed as a partnership files a final Form 1065 for the short period ending the day before conversion. The return is due the 15th day of the third month after that period ends.6Internal Revenue Service. 2025 Instructions for Form 1065 A single-member LLC owner reports the LLC’s activity on the individual return (usually Schedule C) through the conversion date. Mark the final return box so the IRS closes out that classification.
First Return Under the New EIN
The C corporation files Form 1120 for the short period running from the conversion date through year-end. A new corporation’s short-period return is generally due the 15th day of the fourth month after the short period ends.7Internal Revenue Service. Instructions for Form 1120 (2025) For a July 1 conversion with a calendar year, the Form 1120 covers July 1 through December 31 and is due April 15 of the following year.
Income, deductions, and credits have to be allocated between the two returns. Allocation errors can produce underreporting on one side and overreporting on the other, which draws IRS matching notices on both.
Payroll After the EIN Change
If your LLC had employees, the new EIN brings extra payroll paperwork. File final Form 941 (quarterly wages) and Form 940 (federal unemployment) returns under the old EIN through the conversion date. Payroll reporting under the new EIN starts from the conversion date forward.8Internal Revenue Service. Assigning Employer Identification Numbers (EINs)
Watch the Social Security wage base. When a new EIN starts fresh, year-to-date wages don’t automatically carry forward in the IRS system, and that can lead to overwithholding. Tell your payroll provider the conversion date and confirm they track each employee’s cumulative wages internally even though the filings under each EIN cover only part of the year.
Notifying the IRS of Other Changes
Beyond the EIN itself, two other updates often ride along with a conversion.
Business Name
If you’re filing a Form 1120 for the current year, check the name change box on page 1, line E, box 3. If you’ve already filed before the name changed, send a letter to the IRS at the address where you filed. A corporate officer must sign it.9Internal Revenue Service. Business Name Change
Responsible Party or Address
If the conversion changes who the IRS considers the “responsible party” (the person who controls or manages the entity and its funds), file Form 8822-B within 60 days of the change.10Internal Revenue Service. Form 8822-B, Change of Address or Responsible Party – Business The same form handles address changes. This step matters when you’re keeping your EIN. If you obtained a new one, that information was captured during the application.
Getting the Sequence Right
Treating the EIN question as an afterthought is the most common misstep. If keeping your EIN matters to you, file Form 8832 to elect corporate tax treatment before the state-level conversion. Doing it in that order preserves your IRS account, payroll records, and banking relationships.
If a new EIN is unavoidable, work through these items in order:
- Apply for the new EIN on or before the conversion date. You can’t file the corporation’s first return or run payroll without it.
- Notify your bank right away. Some banks update the EIN on an existing account; others require closing the old account and opening a new one.
- Update state registrations, including your state tax account, unemployment insurance, and any professional licenses tied to the old EIN. State timelines vary.
- Tell vendors and clients. Anyone who issues a 1099 for payments to your business needs the new EIN for accurate reporting.
- File final returns under the old EIN, including employment tax returns, and mark each one as final so the IRS closes the old account.
The conversion is a one-time event. Sloppy EIN handling creates notices that follow the business for years.