Your Step-by-Step Guide to Completing IRS Form SS-4

Step

Action

Details & Tips

1. Determine If You Need an EIN

Confirm your business or entity requires an EIN.

You need an EIN if you: Have employees, operate your business as a corporation or partnership, file employment tax returns, withhold taxes on income other than wages paid to a non-resident alien, have a Keogh plan, are involved with trusts (except certain grantor-owned revocable trusts), estates, real estate mortgage investment conduits, nonprofit organizations, farmers’ cooperatives, or plan administrators. Sole proprietors need an EIN if they: Have employees, file excise or alcohol/tobacco/firearms tax returns, or withhold taxes on non-employee income. You may not need an EIN if you’re: A sole proprietor with no employees who uses your Social Security Number for business tax purposes. However, many sole proprietors still obtain an EIN for banking purposes and to keep personal and business finances separate. Tip: Even if not strictly required, obtaining an EIN provides privacy benefits (you won’t need to give your Social Security Number to vendors and clients) and makes it easier to separate personal and business finances.

2. Choose Your Application Method

Decide how you’ll apply for your EIN.

Online (Fastest – Immediate EIN): Free and available for applicants located in the United States or U.S. territories. Apply at IRS.gov through the online EIN application. You’ll receive your EIN immediately upon completion if there are no issues. The session expires after 15 minutes of inactivity, so have all information ready before starting. Available Monday through Friday, 7:00 a.m. to 10:00 p.m. Eastern Time. By Telephone (International Applicants Only): Call +1-267-941-1099 (Monday through Friday, 6:00 a.m. to 11:00 p.m. Eastern Time). The IRS will complete Form SS-4 based on your information and provide your EIN immediately over the phone. This option is only available for applicants outside the U.S. or U.S. territories. By Fax (About 4 Business Days): Complete Form SS-4 and fax it to the appropriate number (855-641-6935 for U.S. applicants). Include your return fax number so the IRS can fax your EIN back to you. Generally receive your EIN within 4 business days. By Mail (4-5 Weeks): Complete Form SS-4 and mail it to the appropriate IRS address at least 4-5 weeks before you need your EIN. You’ll receive your EIN by mail in approximately 4 weeks. Tip: Online application is by far the fastest and most convenient method if you’re eligible. You’ll have your EIN instantly and can begin using it immediately. Avoid applying by mail unless absolutely necessary due to the lengthy processing time.

3. Gather Required Information Before Starting

Collect all necessary information and documents.

Before completing Form SS-4, have ready: Your legal business name (exactly as registered with your state or as it appears on legal documents), trade name or “Doing Business As” (DBA) name (if different from legal name), mailing address and physical address of your business, county and state where your principal business is located, responsible party’s full legal name and taxpayer identification number (Social Security Number, Individual Taxpayer Identification Number, or EIN), business structure (sole proprietor, partnership, corporation, LLC, trust, estate, etc.), reason for applying for an EIN, date business started or acquired, closing month of your accounting year (fiscal year), estimated number of employees in the next 12 months, principal business activity and description. For LLCs: Know the number of LLC members and whether the LLC was organized in the U.S. For Corporations: Know the state or foreign country where incorporated. Tip: Having all information organized before starting—especially for online applications—prevents session timeouts and ensures accurate completion on the first attempt.

4. Complete Line 1: Legal Name of Entity

Enter the official legal name of your business or entity.

Individuals (Sole Proprietors): Enter your full legal name as it appears on your Social Security card (first name, middle initial, last name). Estates: Enter the name of the decedent exactly as it appeared on the decedent’s Social Security card. Trusts: Enter the legal name of the trust as it appears in the trust agreement. Partnerships: Enter the legal name of the partnership as it appears in the partnership agreement. Corporations: Enter the corporate name exactly as it appears in the corporate charter or articles of incorporation. Limited Liability Companies (LLCs): Enter the LLC name exactly as it appears in the articles of organization filed with your state. Plan Administrators: Enter the name of the plan. Other entities: Enter the legal name as it appears on organizing documents. Critical: The name must match your legal documents exactly. Any discrepancies can cause delays and complications with tax filings, bank accounts, and business licenses. Tip: If you’re a sole proprietor and you have registered a trade name (DBA), your personal legal name goes on Line 1, and your business name goes on Line 2.

5. Complete Line 2: Trade Name of Business

Enter any “Doing Business As” (DBA) or trade name.

Enter the trade name of your business if it’s different from the legal name entered on Line 1. This is the name the public knows your business by—the name on your storefront, website, marketing materials, or business cards. Examples: If your legal name is “John Smith” (sole proprietor) but you operate as “Smith’s Plumbing Services,” enter “Smith’s Plumbing Services” on Line 2. If your corporation is legally named “ABC Corporation” but operates as “Sunshine Cleaning Services,” enter “Sunshine Cleaning Services” here. If you don’t have a trade name: Leave Line 2 blank. Many businesses, especially corporations and LLCs, operate under their legal name only. Tip: Make sure any trade name you use is properly registered with your state or local government. Using an unregistered trade name may violate state laws.

6. Complete Line 3: Executor, Administrator, Trustee, or “Care Of” Name

Identify the individual managing the entity (if applicable).

For Trusts: Enter the name of the trustee. For Estates: Enter the name of the executor or administrator. For other entities: Use this line if correspondence should be directed to someone’s attention, such as an accountant or attorney managing the application. If not applicable: Leave this line blank. Most standard businesses will not need to complete this line. Tip: If you complete Line 3, the address you provide on Lines 4a-4b should generally be the address of the person named in Line 3, not necessarily the business address.

7. Complete Lines 4a-4b: Mailing Address

Provide the address where the IRS should mail correspondence.

Line 4a: Enter the street address or P.O. box number where you want to receive IRS correspondence. Include the number, street, and apartment or suite number. Line 4b: Enter the city, town, or post office; state; and ZIP code. For foreign addresses: Enter the city on Line 4a, then complete the additional spaces below for province or state, postal code, and country name. Do not abbreviate the country name. Follow the country’s practice for formatting. Important: This address becomes your official IRS address on file. All IRS correspondence, including your EIN confirmation, will be mailed here. Tip: Use a reliable, permanent address. If you’re working from home temporarily or expect to move, consider using your accountant’s or attorney’s address, or a registered agent service address to ensure you receive important IRS mail.

8. Complete Lines 5a-5b: Street Address

Provide the physical location of your business (if different from mailing address).

Complete these lines only if your business’s physical address is different from the mailing address you entered on Lines 4a-4b. Line 5a: Enter the street address only—do not enter a P.O. box number here. The IRS wants the actual physical location where your business operates. Line 5b: Enter the city, town or post office; state; and ZIP code. For foreign addresses: Enter the city on Line 5a, then complete additional information for province/state, postal code, and country (do not abbreviate country name). If physical address is the same as mailing address: Leave Lines 5a-5b blank. Tip: Your physical address is where the IRS believes your business actually operates. This should be your office, warehouse, retail location, or principal place of business—not a P.O. box or mail drop.

9. Complete Line 6: County and State Where Principal Business is Located

Identify where your main business operations occur.

Enter the county and state where your principal business, office, or agency is physically located. This is typically where you conduct most of your business activities or where your headquarters is located. For businesses operating in multiple locations: Choose the location that represents your primary or main office. For home-based businesses: Enter the county and state of your home address. Tip: This information helps the IRS with geographic tracking and may affect which IRS office handles your account. Be accurate and consistent with the address information provided on Lines 5a-5b (or Lines 4a-4b if you didn’t complete Lines 5a-5b).

10. Complete Lines 7a-7b: Responsible Party Information

Identify the individual who controls or owns the entity.

Line 7a – Name of Responsible Party: Enter the full name (first name, middle initial, last name) of the responsible party. The responsible party is the individual who ultimately owns or controls the entity, or who exercises ultimate effective control over the entity. This is not simply the person filling out the form—it’s the person with ownership or control. Line 7b – SSN, ITIN, or EIN: Enter the Social Security Number, Individual Taxpayer Identification Number, or Employer Identification Number of the responsible party. Who is the responsible party? For sole proprietors: The owner. For partnerships: One general partner. For corporations: The principal officer (president, vice president, etc.). For LLCs: One member or manager. For trusts: The trustee. For estates: The executor or administrator. Important: The responsible party must be an individual (not an entity), except for certain government entities, tax-exempt organizations, and publicly traded companies. Tip: Changes to the responsible party must be reported to the IRS within 60 days using Form 8822-B. Keep this information current.

11. Complete Lines 8a-8c: Limited Liability Company (LLC) Information

Provide LLC-specific details if applicable.

Line 8a: Check “Yes” if your entity is a Limited Liability Company. Check “No” if it is not. Line 8b (if Yes on 8a): Enter the number of LLC members. Count all members, whether individuals, corporations, or other entities. Single-member LLCs enter “1.” Line 8c (if Yes on 8a): Check “Yes” if the LLC was organized in the United States. Check “No” if it was organized in a foreign country. If not an LLC: Check “No” on Line 8a and skip Lines 8b and 8c. Tip: The IRS treats LLCs differently depending on the number of members and elections made. Single-member LLCs are typically disregarded entities (taxed as sole proprietorships), while multi-member LLCs are typically taxed as partnerships unless they elect corporate taxation.

12. Complete Line 9a: Type of Entity

Identify your business structure.

Check one box that best describes your entity type: Sole proprietor: Individual operating a business. Enter your Social Security Number on Line 7b. Partnership: Two or more individuals or entities operating a business together. Corporation: Check this box and specify whether it’s an insurance company or other corporation. Personal service corporation: Corporation where services are performed by employee-owners in fields like health, law, engineering, architecture, accounting, actuarial science, performing arts, or consulting. Church or church-controlled organization: Religious organizations. Other nonprofit organization: Nonprofits other than churches (specify type, such as educational, charitable, etc.). Other: For entities not listed above, check this box and specify. Common examples include “Disregarded entity,” “Governmental,” “Estate,” “Trust,” etc. For disregarded entities: Check “Other” and write “Disregarded entity” or “Disregarded entity-sole proprietorship” if owned by an individual. Line 9b (if Corporation): Enter the state or foreign country where incorporated. Tip: Choosing the correct entity type is critical because it determines how your business is taxed. If you’re unsure, consult with a tax professional before completing this form.

13. Complete Line 10: Reason for Applying

Specify why you need an EIN.

Check the box that best describes your reason for applying. You can only check one box. Common reasons include: Started new business (specify type: sole proprietorship, partnership, corporation, etc.), hired employees, created a pension plan, banking purposes (opening a bank account or establishing business credit), changed type of organization (for example, incorporated a sole proprietorship), purchased going business, created a trust (specify type), other (specify reason, such as compliance with IRS withholding regulations, filing requirements, etc.). For “Started new business”: Specify your entity type in the space provided. For “Other”: Clearly explain the specific reason in the space provided. Tip: Be accurate and specific. The reason you provide helps the IRS understand your tax obligations and may determine which forms and filing requirements apply to you.

14. Complete Line 11: Date Business Started or Acquired

Enter when you began or took over the business.

Enter the month and day the business started or was acquired. For new businesses, this is when you first began conducting business activities (not when you first thought about starting a business). For acquired businesses, this is the date you took ownership. Format: Enter as month/day/year (for example, 01/15/2025). For estates: Enter the date of death. For trusts: Enter the date the trust was legally created or funded. Tip: This date is important for determining when various tax obligations begin. Be accurate—this date will be referenced on future tax returns and may affect filing requirements and deadlines.

15. Complete Line 12: Closing Month of Accounting Year

Specify your fiscal year-end.

Enter the last month of your accounting year or tax year. This is typically the month your business’s fiscal year ends. For calendar year filers (most common): Enter “December.” Most small businesses and individuals use the calendar year (January 1 – December 31). For fiscal year filers: Enter the month that ends your fiscal year (for example, if your fiscal year runs from July 1 to June 30, enter “June”). For certain entities: Some entities have specific requirements. Partnerships generally must use the tax year of the majority partners or principal partners. S corporations must generally use a calendar year unless they can establish a business purpose for a different year. Personal service corporations must use a calendar year unless they meet certain requirements. Tip: If you’re unsure which accounting year to use, choose December (calendar year). You can change your accounting year later if needed, though it requires IRS approval using Form 1128.

16. Complete Line 13: Highest Number of Employees Expected

Estimate your workforce size in the next 12 months.

Enter the highest number of employees you expect to have in the next 12 months. Include full-time, part-time, and seasonal employees. If you’re a sole proprietor with no employees, enter “0.” Count yourself only if you’re an employee of your own corporation. Consider: Current employees, planned hires within the next year, and seasonal workers during your busiest season. Purpose: This information helps the IRS determine your filing requirements, particularly for employment tax returns. Tip: Provide your best estimate. If your actual number of employees differs from your estimate, it won’t invalidate your EIN or cause problems. The IRS uses this for planning purposes, not as a binding commitment.

17. Complete Line 14: Form 944 Election (if applicable)

Indicate if you want to file employment taxes annually instead of quarterly.

This line was reinstated in March 2024. Check “Yes” if you want to file Form 944 (Employer’s Annual Federal Tax Return) instead of filing Form 941 (Employer’s Quarterly Federal Tax Return). You may be eligible for Form 944 if: Your annual employment tax liability is $1,000 or less. Benefits of Form 944: File once per year instead of four times per year, reducing paperwork. Check “No” if: You expect employment tax liability to exceed $1,000 annually, you want to file quarterly (Form 941), or this doesn’t apply to you. Leave blank if: You have no employees or won’t be paying wages. Tip: Most small businesses with employees will use Form 941 (quarterly). Only businesses with very small employment tax liability benefit from Form 944. You can change your election later if your circumstances change.

18. Complete Line 15: First Date Wages or Annuities Were Paid

Enter when you first paid (or will pay) employee wages.

If you checked “Hired employees” on Line 10, enter the date you first paid or expect to pay wages or annuities. If you haven’t paid wages yet but plan to hire employees, enter your expected date. Format: Enter as month/day/year (for example, 03/01/2025). If you don’t have employees and don’t plan to hire: Leave this line blank. Purpose: This date determines when your employment tax obligations begin and when you must start filing employment tax returns. Tip: Be as accurate as possible. This date affects your filing deadlines and determines which quarters you’re responsible for reporting.

19. Complete Line 16: Principal Activity

Describe what your business does in general terms.

Enter a brief description of your principal business activity. The IRS provides examples in the instructions, such as: “Real estate,” “Manufacturing,” “Retail sales,” “Food service,” “Construction,” “Professional services,” “Healthcare,” “Agriculture,” “Transportation,” etc. Use general industry terms: Keep it broad and simple. Don’t get too specific or technical here—save detailed descriptions for Line 17. For trusts or estates: You might enter “Investment” or “Estate administration.” Tip: Think about how you’d categorize your business in a directory or database. Use standard industry terminology rather than creative or marketing language.

20. Complete Line 17: Specific Principal Business Activity

Provide detailed description of your primary business.

Describe in more detail the principal line of merchandise sold, specific construction work done, products produced, services provided, or other business activity. Be specific: If you entered “Retail sales” on Line 16, here you might specify “Women’s clothing and accessories.” If you entered “Construction” on Line 16, here you might specify “Residential home remodeling and kitchen renovations.” If you entered “Professional services” on Line 16, here you might specify “Tax preparation and bookkeeping for small businesses.” Purpose: This helps the IRS understand your business and assign the appropriate business activity code, which is used on your tax returns. Tip: Be clear and accurate. This description should give the IRS a precise understanding of what you actually do to generate revenue.

21. Complete Line 18: Has the Applicant Ever Applied for an EIN?

Disclose any previous EIN applications.

Check “Yes” if the applicant entity has previously applied for and received an EIN. Check “No” if this is the first time applying. If Yes: You may be asked to provide the previously assigned EIN and additional details about why you’re applying again. Important: Generally, each entity needs only one EIN and should file only one Form SS-4. However, you may need a new EIN if: you incorporated a sole proprietorship or formed a partnership, a corporation changed to a partnership or LLC, or you’re taking over an existing business and operating it as a sole proprietorship. Tip: Keep a record of your EIN once received. It’s permanent and should be used for all tax purposes. If you’ve lost your EIN, you can call the IRS Business & Specialty Tax Line at 800-829-4933 to retrieve it rather than applying for a new one.

22. Complete Third-Party Designee Section (Optional)

Authorize someone to receive your EIN and answer questions.

Complete this section only if you want to authorize a specific individual (such as an accountant, attorney, or tax preparer) to: receive the entity’s EIN, answer questions about the completion of Form SS-4. Provide: Designee’s name, designee’s telephone number, designee’s fax number (if available), any personal identification number (PIN) they should use when contacting the IRS. Authority: The designee’s authority automatically terminates once the EIN is assigned and released. This is temporary authorization only for the application process. How EIN is released: The IRS will release the EIN to the designee using the same method they applied (online, phone, fax), but the official EIN notice will still be mailed to the taxpayer. Tip: Even if you have someone helping you apply, you don’t have to complete this section unless you specifically want them to receive the EIN directly and answer IRS questions during processing.

23. Sign and Date the Form

Provide required signature and date.

The application must be signed by an authorized individual: Individuals: Sign if the applicant is an individual. Corporations: President, vice president, or other principal officer must sign. Partnerships: A responsible and duly authorized member or officer must sign. Limited Liability Companies: A member or manager must sign. Trusts: The trustee must sign. Estates: The executor or administrator must sign. Other entities: An authorized individual must sign. Declaration: By signing, you declare under penalties of perjury that you have examined the application and, to the best of your knowledge and belief, it is true, correct, and complete. Applicant’s name and title: Print or type the name and title of the person signing. Signature: Sign in ink (for paper applications). Date: Enter the date you’re signing the form. Tip: Only authorized individuals should sign. Providing false information on Form SS-4 can result in penalties and legal consequences.

24. Submit Form SS-4

Send your application using your chosen method.

If applying online: Follow the online interview process at IRS.gov. Submit electronically. Receive your EIN immediately upon completion. If applying by telephone (international applicants only): Call +1-267-941-1099 with your completed information. The IRS will assign your EIN over the phone. If applying by fax: Fax your completed, signed Form SS-4 to 855-641-6935 (for U.S. applicants). Include your return fax number in the appropriate field. Receive your EIN by fax in approximately 4 business days. If applying by mail: Mail your completed, signed Form SS-4 to: Internal Revenue Service, Attn: EIN Operation, Cincinnati, OH 45999 (for U.S. applicants). Receive your EIN by mail in approximately 4-5 weeks. For international applicants: Use different fax and mail addresses—consult the Form SS-4 instructions for the correct international addresses. Tip: Apply using only one method. Submitting multiple applications can cause confusion and delays. Choose the method that best fits your timeline and situation.

25. Keep Your EIN Confirmation Letter

Save your official EIN documentation permanently.

Once you receive your EIN, immediately save and store the confirmation in a safe place. You’ll need to reference this document frequently. Your EIN confirmation includes: Your nine-digit EIN, your business legal name, your business address, the name and title of the person who applied. You’ll need your EIN for: Opening business bank accounts, applying for business licenses and permits, filing all federal tax returns, preparing W-2s and 1099s, applying for business credit, completing vendor applications, and virtually all official business activities. Make multiple copies: Keep the original in a safe place, save a digital copy in secure cloud storage, provide copies to your accountant and attorney. Tip: Your EIN is permanent and doesn’t expire. You’ll use the same EIN throughout the life of your business. Protect it like you would your Social Security Number—don’t share it unnecessarily, as it can be used for identity theft.

26. Update Your Information If It Changes

Report changes to the IRS promptly.

Use Form 8822-B to report changes to: Responsible party, business mailing address, business location/address. Critical: Changes in responsible party must be reported to the IRS within 60 days. What doesn’t require an update: Minor changes like phone numbers don’t need to be formally reported, though you should update them on tax returns. When you need a new EIN: You generally keep the same EIN, but need a new one if: a sole proprietorship incorporates, a sole proprietorship or individual takes on partners and operates as a partnership, a partnership is taken over by one of the partners and operated as a sole proprietorship, or a corporation changes to a partnership or sole proprietorship. Tip: Keeping your information current helps ensure you receive important IRS correspondence and prevents filing issues. Address changes are especially important—missing IRS mail can lead to serious problems.

Method

Processing Time

Availability

Online

Immediate (instant)

U.S. and U.S. territories only; Monday-Friday, 7 a.m. – 10 p.m. ET

Telephone

Immediate (during call)

International applicants only; Monday-Friday, 6 a.m. – 11 p.m. ET

Fax

Approximately 4 business days

All applicants; 24/7

Mail

Approximately 4-5 weeks

All applicants