Yes. A sole proprietor can use the same EIN for multiple businesses, because the number is tied to you as the taxpayer, not to any single business name or activity. The IRS says directly that you do not need a new Employer Identification Number when you own more than one business, change a business name, or add locations.1Internal Revenue Service. When to Get a New EIN What changes when you add a second or third venture is how you report the income, not how the IRS identifies you.
Why One EIN Covers Every Sole Proprietorship
A sole proprietorship is not a separate legal entity. You and the business are the same taxpayer, so your identifying number, whether an SSN or an EIN, follows you across every sole proprietorship you run. Starting a second consulting practice, an online store, or a freelance photography side business does not create a new taxpayer, and it does not create the need for a new number.
The same logic covers trade names. Any number of “Doing Business As” names can operate under a single EIN. Registering a new DBA or opening a location in a different city is an operational change, not a tax-structure change, so the number stays with you.
How Multiple Businesses Get Reported
The IRS requires a separate Schedule C for each business you operate as a sole proprietor.2Internal Revenue Service. Instructions for Schedule C (Form 1040) (2025) If you run a landscaping company and a web design practice, that is two Schedule C forms, each with its own gross income, cost of goods sold, and deductions. Both carry the same EIN or SSN in the identification field.
Keeping each venture on its own Schedule C gives you a clean profit-or-loss picture for each one and lets the IRS see which business produced which income if a return is examined. The Schedule C instructions are also explicit that if you use part of your home for more than one business, you should not combine the home-office deductions on a single Schedule C.3Internal Revenue Service. Instructions for Schedule C (Form 1040)
Self-Employment Tax Is Combined
Here is where the separate-Schedule-C rule shifts. Self-employment tax is calculated on the combined net earnings from all your businesses on a single Schedule SE.4Internal Revenue Service. 2025 Instructions for Schedule SE (Form 1040) If one business earned $80,000 and another lost $20,000, you owe self-employment tax on $60,000. A loss in one venture reduces the self-employment income from another.
Self-employment tax covers Social Security and Medicare. The Social Security portion (12.4%) applies up to an annually adjusted wage base; the Medicare portion (2.9%) applies to all net earnings with no cap. You must file Schedule SE if your combined net self-employment earnings exceed $400 for the year.5Internal Revenue Service. Schedule C and Schedule SE 1
Payroll Runs Through One EIN
If you have employees in more than one of your sole proprietorships, you still file one set of employment tax returns under your single EIN. Form 941 aggregates wages, withholding, and employer taxes across all your ventures. Your legal name goes on the “Name” line; a trade name can go on the “Trade name” line, but the underlying identification does not change based on which business employs which workers.6Internal Revenue Service. Instructions for Form 941
Keep the Books Separated Even Though the EIN Isn’t
Sharing one EIN doesn’t mean sharing one checkbook. Running every venture through a single account with no internal tracking turns tax time into guesswork, and guesswork is what creates audit exposure on individual deductions.
The cleanest approach is a dedicated bank account for each business. Most banks will open multiple business checking accounts under the same EIN, sometimes with different DBA names attached. Some offer sub-accounts under a primary business account, though those can come with limitations like no debit card access. If one bank won’t accommodate multiple DBAs cleanly, using a different bank for the second venture works.
The same discipline applies to bookkeeping records, invoicing, and receipts. Separated records let you see whether each venture is actually profitable on its own and give you clean documentation if the IRS ever questions a specific deduction on one Schedule C.
The Liability Reality Behind One EIN
One EIN across several businesses is convenient at tax time, but it reflects something worth understanding before you scale: a sole proprietorship gives you zero legal separation between yourself and the business. Every venture you run under that structure shares the same risk pool. If your landscaping business is sued and a judgment exceeds its assets, the plaintiff can pursue income and assets from your web design business, your personal bank accounts, and your personal property.
Running two or three unrelated sole proprietorships under one EIN does not create a firewall between them. A claim against one puts the others at risk along with your personal assets. That is a different situation from operating each venture as a separate LLC or corporation, where the liabilities of one entity generally cannot reach the assets of another. For a single low-risk business, the exposure may not matter much. For multiple ventures involving physical services, customer interactions, or meaningful debt, forming separate LLCs is often the point where the tax simplicity of the sole proprietorship stops being worth it.
When You Actually Do Need a New EIN
Adding a new sole proprietorship business doesn’t require a new EIN. Changing the underlying legal structure does. The IRS lists three situations where a sole proprietor must apply for a new number:1Internal Revenue Service. When to Get a New EIN
- You incorporate. Converting a sole proprietorship into a C-Corporation or S-Corporation creates a separate legal entity that needs its own EIN.
- You form a partnership. Bringing on a co-owner changes the tax structure to a partnership, which files Form 1065 and needs its own number.
- You declare bankruptcy. When a trustee is appointed to administer business assets in bankruptcy, the estate needs a separate EIN.
A few related structural changes trigger the same requirement. Forming a multi-member LLC requires a new EIN, because the IRS generally taxes multi-member LLCs as partnerships. A single-member LLC that elects corporate taxation by filing Form 8832 also creates a new tax entity requiring its own number.
What does not require a new EIN: changing your business name, moving to a new address, opening additional locations, or adding new DBA names.1Internal Revenue Service. When to Get a New EIN Those are operational changes that leave the taxpayer unchanged, which is why one EIN keeps working across every sole proprietorship you run.