The difference between an EIN and a UBI comes down to jurisdiction. An Employer Identification Number is a nine-digit federal tax ID issued by the IRS that identifies your business on federal returns and payroll filings anywhere in the country. A Unified Business Identifier is a nine-digit number issued by Washington State’s Department of Revenue that ties your business to state licensing, tax registration, and agency filings within Washington. They aren’t substitutes for each other. If you run a business in Washington, you generally need both.
What an EIN Does
An EIN is the federal identifier for a business, nonprofit, trust, estate, or similar entity.1Internal Revenue Service. About Form SS-4, Application for Employer Identification Number (EIN) It functions like a Social Security number for the entity, appearing on federal tax returns, payroll filings, and most business financial documents.
The IRS requires an EIN in several situations:
- You have employees on payroll.
- You operate as a corporation, partnership, LLC, or nonprofit, whether or not you have employees.
- You file excise or employment taxes, including a single-member LLC that owes excise tax.
- You administer a trust, estate, or retirement plan.
These triggers come from the IRS’s own EIN guidance.2Internal Revenue Service. Employer Identification Number
A sole proprietor with no employees can use a Social Security number instead. Many still apply for an EIN to avoid giving out an SSN to clients and vendors, and most banks require one before they’ll open a business checking account.
An EIN is free directly from the IRS, and the online application returns your number immediately when you finish.3Internal Revenue Service. Get an Employer Identification Number Sites that charge $75 to $300 to “get your EIN” are reselling a free government service. If the URL doesn’t end in .gov, you’re not on the IRS site.
What a UBI Does
A UBI is what Washington State calls the number the Department of Revenue assigns when you register a business there. It links your business to multiple state agencies at once and doubles as your Washington business license number, state tax registration number, and general state identifier.4Washington Department of Revenue. Business Licensing and Renewals FAQs
The scope is state-level. A UBI covers Washington sales tax, business and occupation tax, state employment obligations, and licensing. It has no federal function. The IRS doesn’t recognize it, and it won’t work on payroll filings, federal returns, or with the Social Security Administration.
A UBI is Washington-specific. If your business is outside Washington, you don’t have a UBI and won’t be asked for one. Your state issues its own identifier under a different name.
How the Two Compare
The core split is federal versus state, and that shapes everything else about how they behave.
- Issuing authority. The IRS issues EINs. Washington’s Department of Revenue issues UBIs.
- Scope of use. An EIN handles federal taxes, payroll reporting, and business banking. A UBI handles Washington state taxes, licensing, and regulatory filings.
- Where it works. An EIN travels with your business anywhere in the United States because federal tax law is uniform. A UBI works only in Washington.
- Cost. An EIN is free from the IRS. Washington charges a fee to register and issue a UBI, and state registration fees generally run from about $35 to $500 depending on entity type.3Internal Revenue Service. Get an Employer Identification Number
- What each one identifies. An EIN identifies the entity to the federal government. A UBI identifies the entity to Washington state agencies.
Because they cover different obligations, having one does not satisfy the requirement for the other. A Washington LLC with employees needs an EIN to run payroll and file federal employment taxes, and a UBI to hold a state business license and remit state taxes.
Do You Need Both?
If you’re forming a business in Washington and any of the EIN triggers apply to you, yes. Corporations, partnerships, LLCs, and nonprofits based in Washington will typically end up with both numbers, as will any Washington sole proprietor who hires employees.
Get the EIN first. State registration in Washington and elsewhere generally asks for your federal EIN as part of the application, so applying for the EIN before you file state paperwork keeps things in order. The IRS online application returns your number in one sitting, which means you can move to the state step the same day.3Internal Revenue Service. Get an Employer Identification Number To use the online tool, your principal place of business must be in the United States or a U.S. territory, and the responsible party — whoever controls the entity’s funds and assets — must have a valid Social Security number or ITIN.5Internal Revenue Service. Instructions for Form SS-4 (12/2025)
If you can’t apply online, Form SS-4 can be submitted by fax with a turnaround of about four business days, or by mail with a wait of roughly four weeks. Applicants whose principal place of business is outside the United States cannot use the online tool and must apply by phone, fax, or mail.5Internal Revenue Service. Instructions for Form SS-4 (12/2025)
Once the EIN is in hand, register with Washington through the Department of Revenue’s business licensing process to get your UBI. That single filing hooks you into the agencies that share the UBI system.
If You’re Not in Washington
Every state assigns a business identifier when you file formation documents, but only Washington calls it a UBI. Depending on where you register, the same kind of number may be labeled an Entity Number, Filing Number, Business ID, Charter Number, or SOS Number. Some states issue a separate state tax ID through their Department of Revenue on top of the Secretary of State registration number, so you can end up with two state-level identifiers instead of one.
The federal side of the picture doesn’t change. Your EIN is the same nationwide, and it’s still the number the IRS, your bank, and your payroll system will ask for. What changes from state to state is the name of the state identifier and the agency you deal with to get it. If someone outside Washington asks for your “UBI,” they most likely mean whatever number your state assigned when you registered.
The Short Version
An EIN is federal; a UBI is Washington. An EIN handles the IRS, payroll, and your business bank account. A UBI handles Washington licensing and state tax. Neither one replaces the other, and a Washington business that meets the EIN requirements needs both, starting with the EIN and then the state registration that produces the UBI.