Basic (02-15)

RM 01001.001 Employer Identification Number (EIN)

A. What is the purpose of an EIN?

  • The EIN is a nine-digit identification number used to search and locate Form SS-4 (Application for Employer Identification Number) that employers filed.

  • The EIN identifies employers in a variety of internal operations and in correspondence regarding employer reporting.

  • The EIN provides a means of comparing and reconciling our records with those of the Internal Revenue Service (IRS).

  • The EIN is the source for the development of various statistics used in the administration of many Federal programs.

B. What is the structure of an EIN?

The IRS assigns the EIN in this format 00-0000000. This table describes what the parts of an EIN indicate.

EIN Part



The EIN is a nine-digit number.


The first two-digits (EIN Prefix) indicate which IRS Campus assigns the EIN.


The last seven-digits indicate the serial portion of the number.

C. Related topics

RM 01001.004 List of Internal Revenue Service (IRS) Campuses with Code and Unique EIN Prefix

To Link to this section - Use this URL:
RM 01001.001 - Employer Identification Number (EIN) - 02/06/2015
Batch run: 02/06/2015