No. An employer’s state ID number is not the same as the federal Employer Identification Number (EIN). The EIN is a single nine-digit number assigned by the IRS for federal tax purposes, while state employer ID numbers are separate identifiers issued by individual state agencies for state income tax withholding and unemployment insurance. A business with employees typically carries at least three distinct numbers: one federal EIN and two state-level IDs, even when it operates in just one state.
How to Tell Them Apart on a W-2
If you’re looking at a W-2 and trying to figure out which number is which, the form itself labels them. Box b, near the top, is labeled “Employer identification number (EIN)” and contains the federal number. Box 15, in the lower section next to the state wage and tax data, is labeled “State / Employer’s state ID number” and contains the state withholding tax ID.1Internal Revenue Service. 2026 General Instructions for Forms W-2 and W-3
The two numbers will almost never match. The EIN always follows the XX-XXXXXXX format. State ID numbers vary in length and format depending on the state that issued them. If your employer operates in more than one state, you may see two sets of state information in Boxes 15 through 20, separated by a broken line. When more than two states need to be reported, the employer issues a second W-2.1Internal Revenue Service. 2026 General Instructions for Forms W-2 and W-3
What the Federal EIN Is
The EIN is a nine-digit number formatted as XX-XXXXXXX, assigned by the IRS to identify a business for federal tax purposes.2Internal Revenue Service. About Form SS-4, Application for Employer Identification Number (EIN) It functions like a Social Security Number for a business. The IRS uses it to track quarterly payroll tax filings on Form 941, annual income tax returns, and the W-2s and 1099s a business issues to workers and contractors.3Internal Revenue Service. Instructions for Form 941
A business needs an EIN if it hires employees, operates as a partnership or corporation, or runs an LLC with more than one member. Sole proprietors without employees can often use their Social Security Number instead, though many choose an EIN to keep personal and business tax activity separate. A business should have only one EIN, no matter how many states it operates in.4Internal Revenue Service. Employer Identification Number
The EIN also carries weight beyond tax filings. Banks generally require it to open a business account for any entity other than a sole proprietorship, and business credit profiles are built around the EIN rather than the owner’s Social Security Number.
What State Employer ID Numbers Are
“State employer ID number” is actually a loose label that covers two separate numbers issued by two different state agencies. Employers in most states need both.
State Withholding Tax ID
The state’s department of revenue (or equivalent tax agency) assigns this number when a business registers to withhold state income tax from employee wages. It appears on state payroll tax returns and in Box 15 of each employee’s W-2. In the nine states with no broad-based personal income tax, a withholding ID isn’t required, though other state registrations may still apply.
State Unemployment Insurance Account Number
The state’s department of labor or workforce agency assigns this separate number for reporting wages and paying state unemployment insurance (SUI) contributions. Every state requires employers to carry SUI coverage, including states without an income tax. That makes the SUI account number a near-universal requirement for any business with employees, even in states where the withholding ID doesn’t apply.
How Many Numbers a Business Ends Up With
A single-state employer typically carries three numbers: one federal EIN, one state withholding ID, and one SUI account number. A business with employees in five states might carry one EIN plus ten state-level numbers. Each state assigns its own pair of identifiers independently, and registration is required in every state where employees work, including states where staff work remotely.
The EIN is the number used on every federal form. State ID numbers appear only on state-level filings: quarterly withholding returns, SUI wage reports, and the state copies of W-2s. State IDs have no use outside of state tax and labor compliance.
Getting the EIN First
A business should obtain its federal EIN before registering with any state, because nearly every state registration form asks for it. The IRS offers a free online application that issues the number immediately, but the session must be completed in one sitting since the tool doesn’t let you save and return, and it times out after 15 minutes of inactivity.5Internal Revenue Service. Get an Employer Identification Number
If the online tool isn’t an option, Form SS-4 can be faxed, with an EIN issued in roughly four business days, or mailed, which takes about four to five weeks.6Internal Revenue Service. Instructions for Form SS-4 (12/2025) For an LLC, corporation, or partnership, the state entity should be formed first; applying for an EIN before the state entity exists can delay things.5Internal Revenue Service. Get an Employer Identification Number
Getting the State IDs
With the EIN in hand, a business registers separately with two state agencies. The first is the state’s tax or revenue department, which issues the withholding tax ID. The second is the state’s labor or workforce agency, which issues the SUI account number. Some states combine both registrations into a single online portal; others require separate filings with each agency.
Registration forms typically ask for the business name, address, entity type, and federal EIN. Many states issue the state ID numbers immediately upon completing the online application. The process has to be repeated in every state where the business hires employees, and a single remote worker in a new state can create registration obligations just as readily as opening a physical office there.