Your employer’s EIN (Employer Identification Number) is in Box b of your W-2, located in the upper-left portion of the form. It’s a nine-digit number in the format XX-XXXXXXX, and it identifies your employer with the IRS the same way your Social Security number identifies you.
How to Spot Box b on Your W-2
The W-2 form follows a standardized layout. Box a contains your Social Security number, and Box b sits directly below it. The label next to Box b reads “Employer identification number (EIN).” The number will always be nine digits separated by a hyphen after the first two, like 12-3456789.
Right below Box b, you’ll see Box c, which lists your employer’s name, address, and ZIP code. Together, these two boxes give you everything you need to identify the company that issued your W-2.
Don’t Confuse the EIN With Nearby Numbers
The W-2 has several number fields that can look similar at a glance, especially if you’re filling out a tax return or entering data into tax software.
- Box a (SSN): This is your Social Security number, not an employer identifier.
- Box b (EIN): This is the one you want. It’s your employer’s federal tax ID number assigned by the IRS.
- Box d (Control number): This is an internal tracking code your employer’s payroll system uses to identify your specific W-2 document. It may be alphanumeric and longer than nine digits, or it may be blank entirely. It is not the EIN.
- Box 15 (State/Employer’s state ID number): This is a state-level identification number, separate from the federal EIN. If your tax software asks for the EIN, Box 15 is the wrong field.
The most common mix-up is between Box b and Box d. If the number you’re looking at has letters in it or is longer than nine digits, you’re probably reading the control number in Box d, not the EIN.
What You Need the EIN For
Most people look up their employer’s EIN because tax software asks for it when they enter W-2 information. Every box on the W-2 maps to a specific field in your return, and the EIN links your reported wages to the correct employer in IRS records. Entering the wrong number can delay processing or trigger a mismatch notice from the IRS.
You may also need the EIN when applying for a mortgage, verifying employment, or filing amended returns from previous years.
How to Find the EIN if Your W-2 Is Missing
If you don’t have your W-2 in hand, you can still track down your employer’s EIN through a few routes. Check a prior year’s tax return, since the EIN appears on every W-2 your employer issued and carries over on filed returns. Your employer’s payroll or HR department can also provide it directly.
If you’re a business owner looking for your own company’s EIN, the IRS suggests checking the original notice issued when you applied, contacting the bank where your business account is held, or looking at past business tax returns. If none of those work, you can call the IRS at 800-829-4933, Monday through Friday, 7 a.m. to 7 p.m. local time. They’ll verify your identity and give you the number over the phone if you’re authorized to receive it.